LIBRARY OF CONGRESS, 

UNITED STATES OF AMERICA. 












i/.m" 






■L 



■ 






■ 






THE 



Practical Catechism 



A COLLECTION OF QUESTIONS ON TECHNICAL 

SUBJECTS, BY MANUFACTURERS 

AND OTHERS, AND OF 

ANSWERS THERETO 



/ 



ROBEKT GKIMSHAW, M.E., Ph.D. 

Author of "Steam Engine Catechism" "Boiler Catechism," 
"Pump Catechism" "Engine Runners' Catechism" "Hints 
to Power Users" " Preparing for Indication," "Engineers 1 
Hourly Log Book," "Saws," "Saw Filing," "Modem 
Milling," "Miller, Millwright, and Mill Fur- 
nisher," "Hints on House Building." etc. 




CO' 



*N r 



NOV 6 J89I 



NEW YORK 

JOHN WILEY AND SONS 

53 East Tenth Street 

1891 



Copyright by 
JOHN WILEY & SONS 

1891 



A 

f \ r-T> tU Carton (ptes* 

171, 173 Macdougal Street, New York 



PREFACE. 



While the questions in this little book of 
reference cover a wide range of inquiry, their 
subjects were chosen by others than the present 
editor, whose task it has been to answer them 
as asked. Some emanate from manufacturers, 
others from merchants, consumers, railway men, 
and those of a hundred divers avocations. Some 
have been put in to be answered through var- 
ious scientific journals and other periodicals; 
others have been put by legal counsel and an- 
swered under oath on the stand, in lawsuits in- 
volving large sums of money. Out of the great 
mass of material at hand in his note books, the 
editor has selected those which he thought 
would most interest the largest number of prac- 
tical men ; and it is to this class of readers that 
the volume is addressed and commended. 

Most of the examples are drawn from actual 
practice. 



Preface. iv. 

While there are in this book some questions 
concerning the steam engine, pump and boiler, 
and the generation and transmission of power, 
the inquirer is respectfully referred, for further 
instantaneous information on these subjects, to 
the author's Steam Engine Catechism, Engine 
Runners 1 Catechism, Pump Catechism, Boiler Cat- 
echism, and Hints to Power Users. 

The reader is advised to consult the Alpha- 
betical Index, which is unusually extended. 



New York, 

September 1 7 1891. 



GENERAL TOPICS. 



PAGE. 

Air, Properties of . . . . 1 

Alloys 6 

Beams 14 

Belts 18 

Bricks 19 

Building 28 

Building Stones 35 

Calculations 37 

Cements 48 

Chemical Processes. . . 51 
Coloring Metallic Ob- 
jects 58 

Combustion 60 

Disinfectants 61 

Fastenings 63 

Fluxes 65 

Foods 66 

Foundry Practice. ... 72 

Fuels 87 

Gas 98 

Gear Wheels.... 100 

Gravity 105 

Hardening, Temper- 
ing, and Annealing 109 

Heating 113 

Hydraulics 119 

Iron and Steel 123 



PAGE. 

Limes, Mortars, and 

Cements 135 

Locomotives 138 

Lubrication 139 

Mechanical Processes 143 
Metals in General. . . . 154 

Millwrighting 156 

Paints, Oils, and Var- 
nishes 161 

Plants 185 

Power 186 

Railways 191 

Ropes 193 

Saws 194 

Shafting 189 

Solders 199 

Strength of Materials. 201 

Sugars 205 

Temperatures 206 

Timber and Trees 213 

Ventilation 220 

Waters 228 

Weights 230 

Wines 235 

Work 239 

Miscellaneous 247 



PRACTICAL CATECHISM. 



AIR* 

Q. How much is an " atmosphere " ? 

A. A pressure of one atmosphere at the level 
of the sea is equal to 14.7 lbs. per square inch, 
being the weight of a column of air one inch 
square, and 27,801 feet high, at a temperature of 
32 deg. Fahr. 

Q. What is the weight of the air at a great 
height above the sea-level ? 

A. At three and a half miles, only about one 
half that at the sea ; at seven miles, one quarter ; 
at ten and a half miles, one eighth ; and at four- 
teen miles, one sixteenth. 

Q. How is it figured up that the air pressure 
upon the body of a man is over fifteen tons ? 

A. Supposing that the area of the surface of 
his body is sixteen square feet ; as he has 
144x14.7 = 2116.8 lbs. pressure upon each square 



*See also under headings Combustion, Heating, and 

Ventilation. 



2 Practical Catechism. 

foot, that will make 2116.8x16 divided by 2240 
equals about 15.12 gross tons of 2240 lbs. each. 

Q. What is the mean pressure of the atmos- 
phere at the level of the sea ? 

A. It is equal to 14.7 lbs. per square inch, or 
2116.4 lbs. per square foot; or to 1.0335 kilo- 
grams per square centimetre. This is called one 
atmosphere of pressure. The following are 
measures of pressures : — 

One atmosphere of pressure : — (1). A column 
of air at 32 deg. Fahr., 27,801 feet, or about 5} 
miles high, of uniform density, equal to that of 
air, at the level of the sea. (2). A column of 
mercury at 32 deg. Fahr., 29.922 inches, or 76 
centimetres high ; nearly 30 inches. At 62 
deg. Fahr., the height is 30 inches. (3). A col- 
umn of water at 62 deg. Fahr., 33.947 feet or 
10.347 metres high ; nearly 34 feet. 

A pressure of 1 lb. per square inch : — (1). A 
column of air at 32 deg. Fahr., 1891 feet high, 
of uniform density as above. (2). A column 
of mercury at 32 deg. Fahr., 2.035 inches or 51.7 
millimetres high. At 62 deg. Fahr. the height 
is 2.04 inches. (3). A column of water at 62 
deg. Fahr., 2.31 feet or 27.72 inches high. 

A pressure of 1 lb. per square foot: — (1). A 
column of air at 32 deg. Fahr., 13.13 feet high, 
of uniform density as above. (2). A column of 



Practical Catechism. 3 

mercury at 32 deg. Fahr., .0141 inch or .359 
millimetre high. At 62 deg. Fahr., the height 
is .01417 inch. (3). A column of water at 62 
deg. Fahr., .1925 inch high. 

The density or weight of one cubic foot of pure 
air, under a pressure of one atmosphere, or 14.7 
lbs. per square inch, is 

At 32 deg. Fahr.=.080728 lb., or 1.29 oz., or 
565.1 grains. 

At 62 deg. Fahr.=.076097 lb., or 1.217 oz., or 
532.7 grains. 

The weight of a litre of pure air, under one 
atmosphere, at 32 deg. Fahr., is 1.293 grams, or 
19.955 grains. 

Q. How do you find the volume of a constant 
weight of air or other permanent gas at any 
other temperature, when the volume at a given 
temperature is known, the pressure being con- 
stant? 

A. Multiply the given volume by the new 
absolute temperature, and divide by the given 
absolute temperature. The quotient is the new 
volume. 

Q. How do you find the increased volume of 
a constant weight of air, starting at 62 deg. Fahr. 
and heated under ordinary atmospheric pressure 
to a given higher temperature ? 

A. To the given temperature add 461, and 



4 Practical Catechism. 

divide the sum by 523 ; this will give the in- 
creased volume by expansion (the original vol - 
ume being counted as 1). 

Q. How do you find the volume of a constant 
weight of air or other permanent gas for any 
pressure, when the volume of a given pressure 
is known ; the temperature remaining constant ? 

A. Multiply the given volume by the given 
pressure and divide by the new pressure to get 
the new volume. 

Q. How do you find the volume of a constant 
weight of air or other permanent gas for any 
other pressure and temperature, when the vol- 
ume is known at a given pressure and tempera- 
ture? 

A. Multiply the given volume by the given 
pressure, and by the new absolute temperature 
and divide by the new pressure, and by the giv- 
en absolute temperature. The quotient is the 
new volume. 

Q. How do you find the pressure of a con- 
stant weight of air or other permanent gas for 
any other volume and temperature, when the 
pressure is known for a given volume and tem- 
perature ? 

A. Multiply the given pressure by the given 
volume, and by the new absolute temperature 
and divide by the new volume, and by the given 



Practical Catechism. 5 

absolute temperature. The quotient is the new 
pressure. 

Q' How do you find the pressure of a constant 
weight of air (or other gas) taken at 62 deg. 
Fahr. and at 14.7 lbs. pressure per square inch, 
with a given volume for any other volume and 
temperature ? 

A. Multiply the initial volume by the final 
temperature plus 461, and divide the product by 
the final volume, and by 35.58. The quotient 
is the new pressure in lbs. per square inch. 

Q. How do you find the pressure of a constant 
weight of air or other gas taken at 62 deg. Fahr. 
and at 14.7 lbs. pressure per square inch, with a 
constant volume, for a given temperature ? 

A. Add 461 to the given temperature, and 
divide the sum by 35.58. The quotient is the 
pressure in lbs. per square inch. 

Q. How do you find the volume of one pound 
of air of a given temperature and pressure? 

A. Divide the absolute temperature (ordinary 
temperature Fahr.-|-461) by the pressure in lbs. 
per square inch, wdth and by 2.7074, to get vol- 
ume in cubic feet. 

Q. How do you find the volume of one pound 
of air under 14.7 lbs. pressure per square inch, 
at a given temperature? 

A. Add 461 to the temperature, and divide 



6 Practical Catechism. 

the sum by 39.80. The quotient is the volume 
in cubic feet. 

Q. How do you find the pressure of one pound 
of air, of a given temperature and volume ? 

A. Divide the absolute temperature by the 
volume and by 2.7074. The quotient is the 
pressure in pounds to the square inch. 

Q. How do you find the temperature of one 
pound of air, of a given temperature and pres- 
sure? 

A. Multiply the volume by the pressure in 
pounds per square inch, and also by 2.7074 ; sub- 
tract 461 from the product. The remainder is 
the temperature. 

Q. How do you find the density of air, at a 
given temperature and pressure ? 

A. Multiply the pressure in pounds per square 
inch by 2.7074, and divide by the absolute tem- 
perature. The quotient is the density, or the 
weight in pounds of one cubic foot. 

ALLOYS.* 

Q. Are there any metals which impart to other 
alloys their own physical properties in the pro- 
portion in which they exist in the alloy ? 



*See also under Coloring Metallic Objects, Hardening, 
Tempering and Annealing, Lubrication, Strength of 
Materials and Solders. 



Practical Catechism. 7 

A. A few — lead, tin, zinc, and cadmium ; 
probably all the rest belong to the other class, 
of which that fact is not the case. 

(Matthiessen.) 

Q. Is the fusing point the same as the solidi- 
fying point ? 

A. Not always. Some alloys, as those of tin 
and lead, will solidify at 181 deg. C, but their 
fusing points vary from 181 deg. C. up to 292 
deg. C, according to their composition. 

Q. How is the separation of the components 
of an alloy very largely prevented ? 

A. By rapid cooling. 

Q. If gun metal is cooled slowly, what is apt 
to be the case with the casting as regards homo- 
geneity or evenness of composition in its various 
parts? 

A. It will be apt to have in it white spots 
looking like tin but really composed of an alloy 
of copper and tin ; and there will be liable to be 
more copper at the top than at the bottom. 

Q. How is it with alloys of silver and gold ? 

A. The only one which will remain uniform 
is 718.97 of silver and 281.07 gold ; the rest will 
contain more silver in the exterior than in the 
center. 

Q. What is the result of trying to make brass 



8 Practical Catechism. 

pipes by squirting, as is done in making lead 
pipe? 

A. The copper is left behind and there is a 
zinc pipe made. The pressure separates the 
metals. 

Q. What will render alloys of lead more 
resistant to hot sulphuric acid ? 

A. A little antimony or copper. (Bauer.) 

Q. Do alloys generally melt at a temperature 
which is the average of their constituents ? 

A. No, they generally melt at a temperature 
below (sometimes very much below) that of 
either metal of which they are composed. 

Q. How about the strength of alloys as com- 
pared with that of the metals which compose 
them? 

A. Generally greater. 

Q. What is the best gun metal ? 

A. Copper 90, tin 10, to copper 91, tin 9. 
More copper than this will make the alloy 
liable to separation in melting. 

Q. What is the "patina" or greenish dis- 
coloration which forms ' on unpolished bronze 
statues ? 

A. Hydrated carbonate of copper. 

Q. What is a test of good tin ? 

A. A mechanical test is that when melted 



Practical Catechism. 9 

and run into drops it should present a shining 
reflecting surface. 

Q. Should gun bronze for casting in chilled 
molds be any different from that cast in sand ? 

A. It should have more copper — say 10 to 1. 

Q. What is the strongest of the bronzes ? 

A. That discovered by Thurston by scientific 
research ; 55 copper, 43 zinc, 2 tin. Its tenacity 
is 65,000 lbs. per square inch ; it is a close- 
grained alloy of rich color, and fine surface, and 
polishes well. It oxidizes with difficulty, has 
considerable hardness and but moderate ductil- 
ity, is tough enough for most purposes, would 
forge if handled skillfully and carefully, and not 
too long nor too highly heated. It is practically 
a brass with a small dose. of tin. 

Q. Is it very essential to see that bronze 
contains no lead if it is intended for tensile 
purposes ? 

A. Yes. Thurston has found one half per 
cent, of lead to reduce the strength of good 
bronze nearly one half and to effect its ductility 
to an almost equal extent. 

Q. How is silicon bronze made ? 

A. Fluo-silicate of potash 450, powdered glass 
600, common salt 250, carbonate of soda 75, 
carbonate of lime 60, dried chloride of calcium 
500. Mix these and heat them in a graphite 



10 Practical Catechism. 

retort nearly to that point at which they react 
upon each other, then place in a copper or brass 
bath which will absorb the silicon. 

Q. What are the merits of silicon bronze ? 

A. It has the conductive qualities of the best 
copper with the resisting powers of iron. 

Q. What alloy can be made of tin and zinc 
which will do instead of brass for anti-friction 
bearings, etc.? 

A. Tin and zinc in equal parts is nearly as 
strong as brass, much cheaper, and a better anti- 
friction metal : but the zinc must be very pure. 
Tin 75 and zinc 25 make good patterns; the 
mixture must not be over-heated, must be 
stirred while pouring ; works easily, turns well 
in the lathe and does not clog the fire. 

(Thurston.) 

Q. What should be the proportion of copper 
and zinc in condenser tubes ? 

A. Copper 18, zinc 30. 

Q. What should be the proportions of copper 
and zinc in boiler tubes ? 

A. Copper 18, zinc 32. 

Q. What of the properties of aluminium 
bronze ? 

A. Copper 90 and aluminium 10 has some- 
times a tenacity of nearly 100,000 pounds per 
square inch ; is hard, stiff, of even quality ; wire 



Practical Catechism. 11 

has had 125,000 pounds per square inch ; is 
very ductile, malleable and tough ; three times 
as stiff as gun bronze and 44 times as stiff as 
brass ; works well, casts well, holds a fine surface 
under the tool and when exposed to the 
weather ; but it is expensive. 

Q. How may the tenacity, elasticity and 
hardness of bronze cannon be increased ? 

A. By driving into the bore a series of conical 
steel mandrils or plugs, thus stretching the metal 
in the interior beyond its elastic limit. 

(Uchatius; Dean.) 

Q. Is it likely that the ancient Egyptians 
and Greeks had the art of hardening brass or 
bronze to the same degree as our steel ? 

A. No ; since no such metal remains ; and we 
have samples of their other or soft brasses. 
The bronze weapons which Schliemann found 
near the site of ancient Troy, were copper 90 to 
96, tin 8.6 to 4. Eeyer found phosphorus in 
some ancient bronze weapons. 

Q. How should crucibles be used in order to 
make them last long? 

A. They should be heated slowly, and at 
first put in the furnace bottom up. 

Q. How is zinc best introduced into melted 
copper ? 



12 Practical Catechism. 

A. It should be wrapped in paper, plunged 
beneath the copper and held there. 

Q. In making alloys, in what order should 
the metals be put in the crucible ? 

A. Other things being equal, the least fusible 
first ; other things also being equal, the least 
volatile first. Zinc and lead being both volatile 
and oxidizable, should go in last. 

Q. Does it make very much difference in 
what order the metals which compose an alloy 
are mixed in it ? 

A. Often a very great deal. Thus 90 tin and 
10 copper, plus 10 of antimony will make an 
alloy entirely different in fusibility, tenacity, 
etc., from one made by adding 90 of tin to 10 of 
copper and 10 of antimony. 

Q. Does the temperature at which an alloy is 
made affect the quality of the alloy itself? 

A. Yes ; for instance, if lead and antimony 
are raised much above their fusing points in 
alloying them, the alloy will be harsh and 
brittle. 

Q. What is the composition of the so-called 
" white bronze " ? 

A. It is made of copper and ferro-manganese, 
the proportion being varied according to the 
purpose for which the alloy is to be employed. 
Forty parts of copper and sixty parts of ferro- 



Practical Catechism. 13 

manganese, with a suitable quantity of some 
appropriate flux, produce a metal of such ten- 
acity that it surpasses the best steel armor 
plates. The melted mixture is cast in blocks 
and is perfectly malleable. To obtain a white 
metal that can be rolled out in sheets the above 
alloy is melted again, and 20 or 25 per cent, of 
zinc and white metal added, which imparts to it 
the desired quality. A plate of the first-named 
alloy, two inches thick, was found by experi- 
ment to offer more resistance to a cannon ball 
than a steel armor plate of the same thickness. 

Q. How can brass be made as malleable as 
copper or iron ? 

B. It is said that this can be done by mixing 
with it about two per cent, of mercury. 

Q. What are the proportions of various 
metallic alloys or compositions in common 
use? 

A. In 100 parts, as follows : — 
Babbitt's Metal Tin 89, Copper 3.7, An- 
timony 7.3. 

Fine Yellow Brass Copper 66, Zinc 34. 

Gun Metal, Valves, etc. Copper 90, Tin 10. 

White Brass Copper 10, Zinc 80, Tin 

10. 

German Silver Copper 33.3, Zinc 33.4, 

Nickel 33.3. 



14 Practical Catechism. 

Church Bells Copper 80, Zinc 5.6. Tin 

10.1, Lead 4.3. 

Gongs Copper 81.6, Tin 18.4. 

Lathe Bushes Copper 80, Tin 20. 

Machinery Bearings.. . .Copper 87.5, Tin 12.5. 

Muntz Metal Copper 60, Zinc 40. 

Sheathing Metal Copper 56, Zinc 44. 



BEAMS, 



* 



Q. What is the rule for the breaking weight 
of a symmetrical, solid beam of rectangular sec- 
tion, supported freely at both ends and loaded 
in the middle only ? 

A. The breaking weight in such case equals 
the product of the breadth by the square of the 
depth, by the ultimate tensile strength per 
square inch, and by 1.155, divided by the span : 
— all being taken in inches. 

Q. When the beam is fixed at both ends and 
loaded in the middle ? 

A. 50 per cent, more than when only freely 
supported. 

Q. When fixed at one end and loaded at the 
other ? 

A. One fourth that of a beam freely supported 
at both ends and loaded in the middle. 



* See also under Building and Strength of Materials. 



Practical Catechism. 15 

Q. When loaded at any other point than the 
middle and freely supported at both ends ? 

A. Then the breaking weight is universally 
proportionate to the segments, or distances from 
the load to the ends, and may be determined by 
first getting the breaking weight of the load in 
the middle, and then making the correction for 
the other point of application. 

(A special question and answer, with calcula- 
tions, in another place, covers these conditions). 

Q. What is the rule when the beam is loaded 
uniformly along its entire length ? 

A. The total breaking weight is twice that 
where loaded at the middle and supported at 
both ends ; or when fixed at one end and loaded 
at the other. 

Q. " How much will a circular wooden beam 
bear before it breaks ?" 

A. Depends on the distance between supports 
and its tensile strength per square inch, also 
where the load is applied. A solid beam of cir- 
cular section 15 inches diameter, 16 feet between 
supports, has a breaking strength at the middle 
of 0.7854 X 15 X 15 X 15 -f- (16x12) times the 
breaking strength per square inch ; and if this 
last is 32,000 lbs., we have a total breaking 
strength of 32,000 X 13.806=44,179 lbs. Inquir- 
ers should state details when writing. 



16 Practical Catechism. 

Q. " How much stronger is a beam or a bridge 
in resisting weight spread all along its lengthy 
than in holding a weight all put in one spot in 
the center ? " 

A. If a beam is supported at both ends and 
uniformly loaded, its breaking strength is equal 
to its breadth, times the square of its depth, 
times its breaking strength per square inch, 
times 2.31, divided by the span. If it loaded at 
the center only, the number 1.155, is used in- 
stead of 2.31. Thus:— take a beam 4 // xl0 // , 
with tensile strength 3500 lbs. per square inch, 
and supported 12 feet equals 144 7/ between sup- 
ports ; if loaded uniformly it would break with 
4x10x10x3500x2.31, divided by 144 equals 
22,358.3 lbs.; while if loaded in the center, 4x10 
xl0x3500xl.55 divided by 144, equals 15,069.4 
lbs. would break it. 

The second result is only half the first. 

Q. "Does it make any difference in loading a 
beam stretched across between two walls, (as a 
traveling foundry crane), whether the load is 
swung from the middle or from one side of the 
middle ? How is it calculated ? " 

A. Suppose the beam is 2x8 inches, and 8 feet 
between supports, and that its tensile strength is 
3000 lbs. per square inch. Then if the weight 



Practical Catechism. 17 

be applied at the center, its breaking strength is 
2X8X8XU55X3000 =4620 ^ 
yb 
But when the weight is 5 feet from one sup- 
port and 3 feet from the other, its breaking 

4x4 16 

strength would be - — 0=77: as much as when 

5X3 15 

the weight was applied at the the center 

= 4 feet from each end. With the weight 

supported 6 feet from one end, 2 feet from 

the other, its breaking strength would be 

4x4 16 4 

- — ^=tt, or - as great as when the weight was 

6X2 12 3 & 6 

slung from the center of the length. With the 

weight exactly at one end, the strength would 

4X4 
be - — ^=inhnitely greater than when being at 
oXu 

the center ; because there would be no load at all 

on the beam. 

Q. " If I have a beam of iron of T section, 
will it be stronger if the flange is put up, or 
down?" 

A. If of cast iron, the flange should be down ; 
that is, supposing that the beam is to be horizon- 
tal and to bear a weight applied in a direction 
tending to break it. If it is under compression 
or under tension lengthwise, it would make lit- 
tle difference which way the flange lies. 



18 Practical Catechism. 

Q. " Should a cast iron I beam have uniform 
section, or have the top flange wider than the 
bottom ?" 

A. Neither. The top flange is in compression 
and the bottom one in tension ; cast is weaker 
in tension than in compression, therefore the 
Lottom member should be of greater cross sec- 
tion than the top. 

Q. "Suppose we are casting I beams; now 
putting the same amount or cross section and 
weight in each case, which is the stronger, one 
2x10 or one 4x8 ; usual proportions being ob- 
served in each case ? " 

A. A beam 2x10 is stronger than one 4x8, 
containing the same amount of material, in the 
proportion of 2x10x10x10 to 4x5x5, or 200 to 
100 ; just two to one. This is supposing both the 
beams are laid on their edges (narrowest sides). 
Laid on their flat sides, their strengths would be 
as 10x2x2 to 5x4x4, or 40 to 80 ; just one to two. 

BELTS. 

Q. Which are the stronger, hemp belts or 
cotton ? 

A. Hemp, by about two to one ; besides which 
hemp breaks strand by strand and thus gives 
warning. 

Q. What is the weight of well-tanned belt 
leather ? 



Practical Catechism. 19 

A. About that of water ; say 62£ lbs. per cu- 
bic foot ; 0.85 lbs. per square foot. 

Q. What is the tenacity of good belt leather ? 

A. About 650 lbs. per inch of width ; 325 
when spliced and riveted ; 220 when laced. 

Q. What is the safe working strain for a leath- 
er belt ? 

A. From 50 to 66 lbs. per inch of breadth. 

Q. What is the strength of raw hide as com- 
pared with leather ? 

A. About one half greater. 

Q. How is belt cement made ? 

A. Melt well together one part of shellac, two 
of pitch, two of linseed oil, four of India rubber, 
sixteen of gutta-percha. Apply warm, thinly 
and rapidly, and clamp the parts together until 
they are well set. 

Q. What is the best dressing for leather belts ? 

A. Castor oil, put on hot and allowed to soak 
well in. Old belts should first be cleaned with 
hot water and soap. Castor oil increases plia- 
bility, durability, and driving power. 

BRICKS* 

Q. How many kinds of building bricks are 
made in the same kiln ? 



*See also under Building and Lime, Mortars and 
Cements. 



20 Practical Catechism. 

A. Three; arch bricks which form the top 
and sides of the arches in which the bricks are 
burned, and which are hard, brittle, and weak ; 
body bricks from the interior of the pile (these 
are sometimes called cherry brick or hard brick), 
and soft sammel (salmon) or pale brick, which 
are from the outside and are underburned. 

Q. What is the test of a good brick ? 

A. Its shape should be regular, surfaces par- 
allel, edges and angles sharp, texture uniform, 
fine and compact ; it should be hard, and ring 
clearly when struck sharply with a trowel or 
with another brick. It should not absorb over 
6 per cent, of its weight of water. 

Q. How much pressure should good bricks 
bear? 

A. 3000 lbs. per square inch. 

Q. Will a wall stand as much pressure per 
square foot as a single brick ? 

A. No. Good quality brick in first quality 
cement should not be given over ten tons per 
square foot. 

Q. How much should ordinary porous per- 
forated bricks stand, in the way of crushing load ? 

A. The bricks alone should stand from 1000 
to 1200 lbs. per square inch, but the brick -work 
itself will not stand one-tenth of this ; being, in 



Practical Catechism. 21 

fact, weaker in proportion than ordinary brick- 
work. 

Q. AY hat are the permissible strains upon 
brick-work, as deduced from actual practice ? 

A. In the excerpt minutes of the proceeding 
of the British Institution of Civil Engineers are 
given the results of some experiments made to 
ascertain the crushing strength of brick -work 
composed of different kinds of brick with vari- 
ous mortars. The mortars used were made of 
either lime or Portland cement, in each case 
mixed with sand, and, as the experiments were 
made by Dr. Bohme, of Berlin, Germany, the 
bricks were those chiefly in use in the city. 
The composition of the mortar was found to 
have great influence upon the strength. Brick- 
work set in a mortar composed of one part lime 
and two parts sand possessed only 44 per cent, 
of the strength of the bricks alone, while a mor- 
tar composed of one part Portland cement and 
three parts sand raised the percentage to 63. 
A great number of tests was made, full partic- 
ulars of each being given. The results obtained 
are summarized in the following table, in which 
the safety limit is taken as one-tenth of the abso- 
lute crushing strength : 



22 



Practical Catechism. 



Description of 
Brick. 



Permissible strain upon 
brickwork with mortar 
composed of 



all 



+3 <D 

a . « 

r-i O CO QO 
l>rH «OTf 



02 03 ^ 



O 02 CO 

rlCOO 



02 £j 

Art 

02 O 
02<4-l 

SCO 



Lbs. 

per 

sq. in. 



Lbs. per square inch. 



Ordinary Stocks.. 
Selected Stocks. . . 

Clinkers 

Porous Bricks 

Porous Perforated 

Bricks 

Perforated do 



2,930 
3,669 
5,390 
2,617 

1,195 
2,759 



129 
162 
237 
115 

53 
121 



139 


161 


176 


202 


259 


296 


125 


144 


57 


65 


132 


152 



185 
232 
341 
165 

75 
171 



The figures are in each case higher than those 
upon which the building regulations of Berlin 
are based. 

Q. How ought a course of brick to run ; with 
the beds perpendicular or not ? 

A. With the beds of the course perpendicular 
or as near that as they can be ; and making the 
bricks upon each course break joint with those 
above and below. 

Q. How much will brick -work weigh ? 

A. About 116 lbs. per cubic foot. 



Practical Catechism. 23 

Q. How many bricks should a bricklayer lay 
per hour ? 

A. From 100 to 200 according to the charac- 
ter of the work. 

Q. What are the dimensions of bricks made in 
different cities? 

A. The standards (which are not always ad- 
hered to) are as follows : — 

Description. Inches. 

Baltimore Front ^ 

Philadelphia Front I 8ix4£x2f 

Wilmington Front J 

Croton Front 8|x4x2} 

Colobaugh 8Jx3|x2f 

Maine 7Jx3|x2| 

Milwaukee 8Jx4Jx2| 

North Eiver 8x3^x2} 

Ordinary { 7|x3|x2} 

J X 8x4Jx2i 

Stonebridge firebrick 9Jx4f x2| 

American (N. Y.) firebrick 8|x4^x2| 
Q. About how many bricks to a square foot 
of wall, in walls of various thickness ? 
A. 4 inch wall 7 per square foot. 

q a u 14 " " u 

13 " " 21 " " " 
18 " " 28 " a " 
22 " " 35 " " " 



24 Practical Catechism. 

Q. How are corners in brick -work measured 
and charged for ? 

A. Twice. 

Q. About what is the proportion of brick to 
mortar in ordinary brick -work ? 

A. About five to one. 

Q. What is the rule for height of brick walls 
as compared with their thickness ? 

A. That for first class buildings with good 
workmanship, the general average should not 
exceed a greater number of feet in height than 
three times the thickness of the walls in inches ; 
and the length not to exceed double the height 
without lateral support of walls or buttresses, 
thus : 

Thickness. Safe Height. Length. 

8J in. 25 ft. 50 

13 " 40 " 80 

17 " 55 " 110 

22 " 66 " 130 

26 " 78 " 150 

Where the lengths must exceed these pro- 
portions, as in depots, warehouses, etc., the 
thickness should be increased, or lateral braces 
instituted as frequently as practicable. 

Q. How strong is the mortar in a brick wall, 
compared with the wall itself? 

A. That depends upon the kind of mortar. 



Practical Catechism. 25 

Brick-work set in mortar composed of one part 
of lime and two of sand has only forty-four per 
cent, of the strength of the bricksjalone ; while a 
mortar of one part of Portland cement and three 
of sand raises the percentage to sixty-three. 

Q. "I am about to put up a brick wall 1J 
bricks thick and 40 feet high; the ground is 
clay. Could I put up the wall of brick direct 
on the earth, with no foundation any thicker 
than the wall itself?" 

A. A brick wall 12 inches thick and 40 feet 
high will weigh about 5,200 lbs. for every foot 
in length, and will therefore exert a pressure of 
30 lbs. per square inch upon the earth beneath 
it. This is too much to be borne upon the area 
of a strip of earth one foot wide ; the founda- 
tion should be at least 18 inches wide, so as to 
make the pressure only 24 lbs. per square inch, 
and even this is excessive. 

Q. In specifying about brick work, how can I 
express the best way as regards thickness of the 
joints? 

A. Put it about this way : that if the bricks 
are two and three quarter inches thick, four 
courses when built shall not measure more than 
one foot in depth ; that will keep the joints 
from being more than one-fourth of an inch in 
average thickness. Thus: Two and three- 



26 Practical Catechism. 

quarters by four equals eleven inches for the 
bricks alone ; and with one layer of mortar for 
each brick, that makes twelve inches. 

Q. How may the volume of brick work in a 
chimney of square cross section and with taper- 
ing sides and straight floor be approximated 
without going through the regular process of 
finding the exact volume by getting the mean 
proportional to the areas of the top and bottom, 
etc.? 

For instance, suppose a square stack 9 inches 
thick at the top and 24 at the bottom ; and 
having a flue 22 inches diameter both top and 
bottom ; what is the approximate solid contents, 
if the height be 50 feet? 

A. The average thickness is (9-)-24)-f-2=16^ 
inches ; the average of the perimeters (inside 
and out) is (22+16£)x4=154 inches; the 
approximate cross section 154 X 16 J= 2,541 
square inches or 2,541 ■— 144= 16.56 square feet ; 
and on this basis the approximate volume 
would be 17.56x50=888 cubic feet. 

The actual volume by the proper rule, using 
the mean proportional, is 909 cubic feet ; the 
approximate volume being (909— 888) -^ (909 X 
100) =2 T 3 o 1 o per cent, too small. 

Q. What are fire bricks? 

A. They are made of nearly pure clay or of 



Practical Catechism. 27 

pure clay with clean sand, or sometimes of 
nearly pure silicate with a small proportion of 
clay. 

Q. What is an injurious element in fire 
brick ? 

A. Iron ; 6 per cent, of which should deter- 
mine its rejection ; and lime, soda, potash and 
magnesia, 3 per cent, of which four together 
should also call for rejection. Iron pyrites is 
worse than any of the others mentioned. 

Q. Where fire bricks are to stand heat solely, 
of what should they contain most ? 

A. Silica. 

Q. W T here they are to stand the action of 
metallic oxides, of what should they contain 
the most ? 

A. Alumina, as silica would tend to unite 
with the metallic oxides. 

Q. How many fire brick should a workman 
lay per hour ? 

A. About 60. 

Q. How are fire bricks usually set in bridge 
walls and furnace linings ? 

A. With mortar instead of cement, and with 
too thick joints. Use a thin cement, put on 
with a whitewash brush, and you will not so 
soon be bothered with crumbling bridge walls. 



28 Practical Catechism. 

building.* 

Q. What is the objection to bush-hammering 
sandstone ? 

A. It makes it liable to scale. 

Q. In masonry what should be the propor- 
tions of the stone ? 

A. If soft they should have a depth of one- 
third their length to prevent their cross-break- 
ing, and a breadth of half their length. Hard 
and strong stones may have double the length. 

Q. In course masonry what should be the 
proportion of headers ? 

A. At least one quarter of the stones should 
run clear through from front to back. 

Q. What is the strength of rubble masonry ? 

A. Not more than that of the mortar. 

Q. What is the strength of course and fine 
masonry ? 

A. Almost as great as that of the separate 
stones. 

Q. In measuring up masonry, how are the 
openings for doors and windows counted ? 

A. If less than three feet wide they are 
counted as solid wall ; and 18 inches is added 
for each jamb. 



*See also under Bricks, Building Stones, Limes, 
Mortars and Cements, Strength of Materials, Timber 
and Ventilation. 



Practical Catechism. 29 

Q. Where a contract is made for masonry at 
so much a cubic yard, does that include the 
cost of scaffolding, etc.? 

A. It generally includes furnishing every- 
thing except the cement ; includes scaffolding, 
centering, cost of delivery and risks from any 
source. 

Q. Is there any way of making slate roofs 
with a very flat pitch ? 

A. They have been laid with a pitch as flat 
as only one-half inch per foot ; each slate being 
exposed full face to the weather, and laid in 
cement consisting of liquid coal-tar thickened 
with cement or ground slate, slacked lime and 
linseed oil ; the compound being applied hot 
and the joints payed. 

Q. How is the Willesden waterproof building 
paper used in England prepared ? 

A. The principle upon which the water- 
proofing is done is very simple. Cellulose 
(woody fiber) is dissolved in an ammonia 
solution of copper, and is then used as a varnish 
or bath for waterproofing. This ammonia 
solution is made by dissolving copper in strong 
ammonia (.880 deg. of the photographers) in 
the presence of atmospheric air. A bath con- 
taining some copper wire or chips of clean cop- 
per is filled with the strong ammonia, and left 



30 Practical Catechism. 

with the cork partly out to admit access of air. 
Three or four inches of copper wire per ounce 
of solution is sufficient. When a deep blue color 
has been acquired, some pieces of clean white 
blotting paper are dissolved. The liquid is 
ready for use. Applied to wood its appearance 
is like that of blue paint. 

Q. How can elevator shafts be made fire- 
proof? 

A. By lining with corrugated iron — or better 
yet, bright tin — securely fastened to the wood- 
work. 

Q. What makes the best fireproof doors ? 

A. Hard wood covered with tinned iron. 
The wood must be in two layers, each tongued 
and grooved, and one layer crosswise of the 
other. 

Q. To get the light reflected well back into a 
room should the window be near the ceiling or 
not? 

A. For a given height of window opening it 
is best to have it near the ceiling so that the 
light may be reflected at a flatter angle. 

Q. What are the usual maximum loads to be 
expected on various kinds of floors ? 

A. In addition to the weight of the floor it- 
self;— 



Practical Catechism. 31 

Per sq. ft. 

For Steel Bridges 80 

u Floors of Dwellings 40 

" Churches, Theatres, and Ballrooms . 80 
" Warehouses and Merchandise .... 250 
" Factories 200 to 400 

Q. What are the normal maximum weights 
of roofs ? 

A. The following give average roof weights, 
plus an allowance of 30 lbs. per square foot for 
snow weight and wind force : — 

Per sq. ft. 
Corrugated Iron, laid directly on purlins . 37 

" " " on boards 40 

Slate nailed to boards 46 

" plastered below rafters 56 

Q. How much stiff soil should a strong plough 
with two good horses and two men loosen up 
per day of ten hours ? 

A. About 200 to 300 cubic yards. 

Q. What are the advantages of concrete 
bridges ? 

A. They are solid, without being dead and 
rigid like stone or brick ; do not require expen- 
sive appliances nor skilled men to put them up, 
and get stronger with age, besides being capable 
of being rapidly put up. 



32 Practical Catechism. 

Q. How can the elasticity of asphaltum be 
preserved, in places where a coating of it would 
be liable to fracture, as on roof-tops, etc.? 

A. Mix a little air-slaked lime or clean fine 
sand with the material while hot. (This ap- 
plies to asphaltum only ; not to coal-tar, often 
miscalled asphalt.) 

Q. How do you get the measurement of stand- 
ing timber ? 

A. The "customary" measurement of stand- 
ing timber is different from the " true " measure- 
ment. In either case sometimes one-eighth 
the girth is allowed for bark, and sometimes 
one-tenth. Where one-eighth is allowed the 
customary measurement is got by multiplying 
the square of the circumference in inches by 
the length of the tree in feet and dividing by 
3009; and the true contents is got by using 
2360 for the divisor instead of 3009. Where 
one-tenth is allowed for bark the divisors are 
2845 for customary measure and 2231 for true 
contents. 

Q. What is meant by the " angle of repose ? " 

A. (1) The steepest angle, with the horizon- 
tal, made by the side of a bank or pile left free 
to take its own shape ; that angle below which 
the material will not slide. Thus for lime dust 



Practical Catechism. 33 

it is 45 deg., wheat flour 44 deg., malt flour 
40 deg., sawdust 44 deg., dry sand 40 deg., 
sand less dry 39.6 deg., wheat grains 37 deg., 
malt grains 37 deg., common mould 37 deg., 
peas 35 deg. — all the foregoing being deter- 
mined by letting them fall from a spout. Coarse 
gravel in heaps takes 35 to 38 deg., common 
gravel 35 to 36 deg., large flints 40 to 45 deg., 
flints half the size of those last mentioned 35 
deg. 

(2) The steepest angle with the horizontal, 
at which one timber or stone will lie on another 
piece of material without sliding. In this case 
we may get the "coefficient of friction" by 
taking the tangent of the angle of repose — 
this being the vertical distance from the end 
of a horizontal radius one foot long, to the 
prolongation of the other radius enclosing the 
angle. 

The following table, from Haswell, gives the 
coefficient and angles for various building mater- 
ials : — 



34^ 



Practical Catechism. 



d o §£> 



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s,H "rf 

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M & OT 3 v &> 


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CO 
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Tab 


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v ° ^ "^ i>- JT^ P 


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Practical Catechism. 35 

building stones. 

Q. What is sandstone ? 

A. A rock having strata, and composed of 
grains of sand (silex) cemented together by a 
natural cement usually composed of silex, lime 
and alumina. In the best stone the cement is 
almost all silex, and in the poorest, largely 
alumina. 

Q. What is the effect of lime in sandstone ? 

A. To make it disintegrate in impure atmos- 
phere, or in foundations where it is liable to be 
attacked by water containing acid. 

Q. What are the best indications of sand- 
stone ? 

A. It should have a small grain, small pro- 
portion of cementing material, and sharp bright 
clear fracture. 

Q. How should sandstone be laid in build- 
ing? 

A. In the same direction as its natural bed. 

Q. What is gypsum ? 

A. The same as alabaster or plaster of Paris ; 
a sulphate of lime having in it some water of 
crystallization. 

Q. What are injurious constituents of fire 
stone ? 

A. Lime and magnesia (except as silicates) ; 



36 Pbactical Catechism. 

potash makes fusible stone ; quartz and mica 
make infusible stone. 

Q. What is the effect of fire upon lime-stone ? 

A. Upon most of them to crumble them ; 
some of them which contain oil (particularly if 
they have silicate or alumina) stand fire well. 

Q. What is the result of fire upon granite, 
gneiss, syenite, quartz, mica, slate, and the other 
primary rocks ? 

A. They crack and explode. 

Q. What is the most refractory building 
stone ? 

A. Sandstone free from felspar, somewhat 
porous and uncrystallized. 

Q. Are concrete and beton walls fire proof? 

A. They do not resist fire very well. 

Q. In masonry walls what is it that really 
determines the crushing strength ? 

A. The strength of the mortar or cement in 
which the stone or bricks are laid. 

Q. What determines the durability of build- 
ing stone ? 

A. Their strength, hardness and porosity. 
The amount of water which they absorb is some 
test of their lack of durability ; those which ab- 
sorb the least being the most durable, other 
things being equal. 



Practical Catechism. 37 

Q. What is the effect of iron in a building 
stone ? 

A. If in the form of protoxide it is liable to 
further oxidize and then cause disintegration. 

Q. What is the relative durability of Port- 
land sandstone and Florida coquina ? 

A. It has been estimated that the former 
would take 2003.3 years to disintegrate it to the 
depth of one-tenth inch, while the latter would 
require only 6.92 years. 

calculations.* 

Q. What are the meanings of the lines A, B, 
C, D, on the slide rule ? and how are they 
worked to do any good ? 

A. The lettering is purely arbitrary. A, B 
and C are alike, each having two similar sets of 
graduations ; that is, there are 6 sets all alike, 
in 3 sets of 2 each. If you want to multiply 18 
by 8.6, set 1 of B opposite 18 upon A, and oppo- 
site 8.6 at B, will be the product. Thus : 

A 18 155 

B 1 8.6 

The answer is really 154.8, but upon small 

*See also under nearly all the other heads in other 
than chemical lines. 



38 Practical Catechism. 

rules you can not read down quite so fine as 
that. The D scale is for squares and square 
roots. To get the square root of 324 set C 1 
and D 1 together, then opposite C 324 is the 
square root 18 upon D. 

Q. A child born weighing eight pounds was 
laughingly said to double his weight every day. 
How much would he weigh at this rate, in 
thirty-three days ? 

A. The thirty-second power of 2 is 4,294,- 
967,296, which multiplied by eight is 34,359,- 
738,368 as the weight in pounds ; say 17,179,869 
and a fraction net tons. 

Q. How do you find out what circle has one 
square inch of area ? 

A. The area of any circle is equal to 0.7854 
times the square of its diameter. Thus the 
area of a circle one inch in diameter is equal 
to 1X1X0.7854=0.7854 square inch. Putting 
the thing the other way about, the diameter of 
any circle is equal to the square root of the quo- 
tient of its area by 0.7854. As the quotient of 
1 by 0.7854 is 1.27324, and the square root of 
1.27324 is 1.1284, it follows that a circle 1.1284 
inches diameter has an area of one square inch. 

Q. What is the area of a field having two 
sides 55 and 59 rods respectively, enclosing a 



Practical Catechism. 



39 



right angle ; and two other sides 28 and 75 feet 
respectively ; and how is it determined ? 




A. The quickest way is to lay the field down 
to scale and run over it with a planimeter. By 
this method the area is 2750 rods. Another 
method is as follows : Draw a diagonal A con- 
necting the ends of the 55 and 59 feet sides AB 
and BC. This is the hypothenuse of a right 
angled triangle ABC, and its length is V55' 2 -)-59' 2 
= \ 3925+3481= I 7 6566, practically 81 rods. 

The area of the right angled triangle ABC is 
equal to 59x55-^-1622.5. The area of the sca- 
lene triangle ACD is found as follows : 



40 Practical Catechism. 

Add the three sides together ; divide the sum 
by 2 ; from the half sum, substract each side 
separately; multiply the half sum and the 
three remainders continuously together; take 
the square root of the product. 

Thus :—28+75+81=184 ; 

184--2=92; 92—28=64; 92—75= 
17 ; 92— 81=11 ; 92x64x17x11=1,101,056 ; 
Vl,101,056=1049.312, which is the area of the 
second triangle. Then 1622.5+1109.9=2671.8 
square rods. 

Q. " I have a triangle with sides 25, 30 and 
60 feet, and do not know the angles between 
them, and want to get the area; do not care 
about the angles, anyhow; want to know if I 
can get the area without knowing the angles, 
or anything but the three sides ? " 

A. There can be no such triangle. Lines 25, 
30, and 60 feet long will not inclose a triangle, 
as can readily be seen by attempting to lay it 
out to scale. But supposing one of the sides 
was 35 instead of 60, the area could be found 
thus : Take the sum of the sides ; it is 90. 
Halve this ; you get 45. Take each side, sepa- 
rately, from the 45 ; you have 20, 15, and 10. 
Multiply the 45 and these three remainders 
consecutively; 45x20x15x10=135,000, The 



Practical Catechism. 41 

of the triangle will be the square root of this 
last product ;=367.4. 

Q. How do you ascertain the area of an ir- 
regular figure? 

A. (1). Draw a line through to its extreme 
dimensions ; divide this line into ten or twenty 
equal parts; at the middle width of each di- 







3 




























7 








1 


2 


3 


4 


5 


6 


7 


S 


— J— 
9 


lOJ 











Fig. 2. 

vision erect perpendiculars clear across the fig- 
ure ; add together the length of the lines, divide 
by the number of measurements, and multiply 
the quotient by the length of the first line 
drawn. If the figure has re-entrant outlines so 
that some of the measuring lines are not wholly 
within the figure, measure only those portions 
which are within its boundaries. Thus in Fig. 



42 



Practical Catechism. 



2, lines 3 and 7 should be measured only where 
shown full. 

(2). Draw the figure on a piece of paper or 
cardboard of uniform quality and thickness; 
cut it out carefully and weigh it accurately ; 
weigh ten or any other even number of square 
inches of the card and get the area of the irreg- 




ular piece, by proportion. Thus if 10 square 
inches weigh 28 grains, and the diagram weigh 
7 grains, its area is 7 X 10-^28=2.5 square inches. 
Q. In order to find the size of round pipe 
which will have the same section as a square 
one, what must be done ? 



Practical Catechism. 43 

A. Multiply the diameter of the circle by 
0.88623, and you will get the area of a square of 
the same area — more than near enough for all 
practical purposes. Multiply the side of the 
square by 1.12838, and you will have the diam- 
eter of the equivalent circle. Thus it will take 
a round pipe 11.2838 inches bore to have the 
same area as a square one 10 inches inside di- 
ameter (not diagonal). 

Q. How do you find out how much wire it 
takes to wrap around a cylinder in a spiral ? 

A. Multiply the circumference of the base by 
the number of revolutions of the spiral, and to 
the square of the product add the square of the 
height ; the square root of the same will be the 
length of the spiral. The diameter of the cyl- 
inder must be considered as extending to the 
middle of the thickness of the wire. 

Q. What is the way to find the force of a 
screw ? 

A. Multiply twice the periphery by the ra- 
dius of the hand wheel or lever, then divide 
this by the pitch of the screw threads. Allow 
for friction, say 25 per cent. 

Q. In ciphering up for a coal pocket, how 
many cubic feet should I allow for each ton ? 

A. Solid coal runs from 80 to 100 lbs. per 
cubic foot, averaging 87 i lbs. Heaped coal 



44 Practical Catechism. 

runs 45 to 56 lbs. per cubic foot, averaging 51| 
lbs. A ton of heaped coal takes from 40 up to 
49f cubic feet, averaging 43 J cubic feet. 

Q. What is a " cylindrical foot ? " 

A. The volume of a cylinder a foot long and 
a foot in diameter, or having an area of head of 
0.7854 feet. Thus, the weight of a cylindrical 
foot of water, at 62 deg. Fahr., is 48.973 lbs.; 
that of a cubic foot, 62.355 lbs. Then a 
cylinder (such as a pipe) a foot in diameter and 
100 feet long, contains 48.973x100=4897.3 
lbs. of water at 62 deg. Fahr. If it is two 
feet in diameter and 100 feet long, it contains 
2X2X100X48.973=19,589.2 lbs., avoirdupois. 

The use of the " cylindrical foot " to civil en- 
gineers dealing with water works, etc., is appar- 
ent. Now, to the steam engineer. We will 
suppose that he has a boiler 60 inches diameter 
and 14 feet long, and wants to know what 
weight of water it will hold at 62 deg. Fahr. 
when half full. 

It contains 5X5X14=194 cylindrical feet 
whenfull ; then, of course, 97 cylindrical feet 
when half full ; and that will weigh 97x48.973 
=4750.381 lbs. at 62 deg. Fahr. 

A pump barrel, 6-foot stroke, 2 feet diameter, 
contains 2x2x6=24 cylindrical feet; and if 
filled with pure water at 62 deg. Fahr., at each 



Practical Catechism. 45 

stroke its contents would weigh 24x48.973= 
1175.352 lbs. avoirdupois. 

For a rough, quick approximation, allow 
50 lbs. per cylindrical foot for the weight of 
water. 

Q. How do you compute the volume of 
round timber, when all dimensions are in feet ? 

A. Add together squares of diameters of 
greater and lesser ends, and product of the two 
diameters ; multiply the sum by 0.7854, and the 
product by one-third of the length. Kesult will 
be in cubic feet. 

Q. How when length is in feet and diameters 
in inches ? 

A. Find as above and divide by 144 ; or use 
0.005454 as a multiplier instead of 144. 

Q. How when all dimensions are in inches ? 

A. Same as when all are in feet, then divide 
by 1728 ; or use 0.0004545 as a multiplier in- 
stead of 0.7854. 

Q. How do you get the contents of a turnip- 
shaped body ? 

A. Multiply the length of the short axis by 
the square of the long one, and the product by 
.5236. 

Q. How do you compute the weight of a cast 
iron spherical shot ? 



46 Practical Catechism. 

A. Multiply the cube of the diameter in in- 
ches by .1365 for the weight in pounds. Thus 
a 5-inch shot weighs 1 25 X- 1365 =17.062 lbs. 

Q. How do you get the diameter of a cast * 
iron spherical shot from the weight ? 

A. Divide weight in pounds by .1365 and ex- 
tract the cube root for diameter in inches. 

Thus a cast iron spherical shot to weigh 1000 
lbs. should be 3 Vl000-5-1365= 3 ^7326.07= 19.4 
-[-inches. 

Q. How do you figure the number of round 
shot in a full triangular pile ? 

A. Multiply the number of shot in one side 
of the bottom course by that number plus one, 
and that number by two, and divide by 6. 
Thus if there are ten on a side the number will 
be 10x11x12^6=1320-^6=220; if there are 
^ye on a side, 5x6x7-f-6=35. 

Q. How do you compute the number of 
round shot in a full square pile ? 

A. Multiply the number in one side of the 
bottom course by itself plus one and by double 
itself, plus one, and divide by six. Thus for ten 
on a side, 10x11X21 -s-6=385; for five on a 
side, 5x6x11-5-6=55. 

Q. How do you figure the number of round 
shot in a complete oblong pile ? 



Practical Catechism. 47 

A. From 3 times the number in the base 
course subtract one less than the number in 
the breadth of it; multiply the remainder by 
the number in the breadth, and again by the 
breadth, increased by 1, and one-sixth of the 
product will give the number. 

Q. Kequired the thickness of cast iron for 8- 
inch diameter steam pipes to be safe from burst- 
ing, with 80 lbs. steam per square inch on the 
boiler ? 

A. There are few things in which rules are 
more widely divergent than strength and thick- 
ness of cast iron pipes. Hawksley's rule gives 
the thickness for water pipes as pressure in 
pounds per square inch times inside diameter 
in inches, divided by twice the tensile strength 
of the material, times the factor of safety, and 
plus a constant correction for imperfections of 
process, method and workmanship. With a 
factor of safety of 6, and tensile strength of 
18,000, that would give (leaving out the correc- 
tion) for 8-inch pipes to stand 80 lbs. internal 
pressure, (6 X 80x8) -*-36,000=. 10007 inch, to 
which the " correction " might be .25, making 
the pipe .35 inch thick. His special formula 
for 200 feet head of water (or 88.6 lbs.) is .021, 
which would give .25+(,02lX8)=.25-hl68= 
.418 inch. 



48 Practical Catechism. 

Bateman's rule gives the thickness as equal to 
the pressure in pounds per square inch, times 
the diameter in inches, divided by 4250, and 
plus .25, which would give (80x8)-i-4250 and 
plus .25; or 155+.25=.405 inch. 

D. K. Clark's table gives an 8-inch pipe .5 
inch thick an actual bursting pressure of 1960 
lbs. and giving a factor of safety of 15, al- 
lows 133 lbs. per square inch. 

Trautwine cites Eeuleaux and Lame for this 
rule : Divide the ultimate cohesion of the ma- 
terial in pounds per square inch by the factor of 
safety ; divide this quotient into the pressure in 
pounds per square inch. To half this quotient 
add 1. Multiply the sum by the quotient to 
which you added 1, and multiply the product 
by the minor radius in inches. This would 
give, in the case cited, 18000-^-9 = 2000; 80-h 
3000=.0375 ; .0375 -v- 2 =.01 875 ; 1+.01875= 
1.018775; 1.01875 X. 0375 X4-S-.1528. But Traut- 
wine adds to the 3.8 inches which his rule 
gives him for a 14-inch pipe to stand 2000 
lbs. per square inch (with a factor of safety 
of 4) .5 inch for irregularities of casting, etc. 
So we might as well come down to rule of 
thumb, or guess work, and make it a half inch 
pipe. 



Practical Catechism. 49 

cements* 

Q. Is there such a thing as a "Universal 
Cement," that is, one which will stick anything ? 

A. Prof. Alexander Winchell is credited with 
the invention of such a cement that will stick 
on anything. Take 2 ounces of clear gum 
arabic, 1J ounces of fine starch, a half ounce of 
white sugar. Pulverise the gum arabic and 
dissolve it in as much water as the laundress 
would use for the quantity of starch indicated. 
Dissolve the starch and sugar in the gum 
solution. Then cook the mixture in a vessel 
suspended in boiling water until the starch 
becomes clear. The cement should be as thick 
as tar and kept so. It can be kept from spoiling 
by dropping in a lump of gum camphor, or a 
little oil of cloves or sassafras. This cement 
is very strong, and will stick perfectly to glazed 
surfaces, and is good to repair broken rocks, 
minerals or fossils. 

Q. How is " flexible mucilage " made ? 

A. By adding to 20 parts of alcohol, one part 
of salicylic acid, 3 of soft soap and 3 of glycer- 
ine ; shaking and then adding a mucilage of 93 
parts of gum arabic and 180 of water. 

Q. " I have in use at my corn mills a 48 inch 



♦See also under Fastenings. 



50 Practical Catechism. 

diameter boiler shell with 11 flues, 7 inches in 
diameter, used as a dryer for corn. Two of the 
flues leak steam badly. How can I remedy the 
matter without tearing into the shell? Some 
sort of sticky adherent coating for the inside of 
flues is what is wanted. Have tried sal 
ammoniac, bran and manure — with no good 
results. Leaks are not bad ones, but it is bad 
to have any in a dryer for corn. If it was a 
horizontal boiler, the mud would stop the leaks 
and they would not show, but being merely a 
steam drum the leaks gradually cut larger from 
the clear steam. Dryer stands upright (on end) 
Steam and return pipes enter at bottom or near 
bottom." 

A. A good cement for iron boilers is made of 
red or white lead in oil 4 parts, iron borings 
3 parts. A rust-joint may be made of clean iron 
borings 2 parts, flowers of sulphur y 1 ^, sal 
ammoniac j 1 ^. Another rust-joint mixture is 
finely powdered iron borings 1 part, sal ammon- 
iac i, flowers of sulphur j 1 ^. Pound together 
and keep dry. For use mix 1 part with 20 of 
iron borings, and mix to a mortar consistency 
with water. If you could get at the joint it 
would be well to partially melt 2 parts of 
sulphur and add 1 part of fine black lead 
(plumbago; graphite). 



Practical Catechism. 51 

Q. What is the cement most commonly used 
for iron ? 

A. Pulverized sal ammoniac crystals, sulphur, 
iron filings, and urine or water, but it sets very 
slowly, sometimes taking weeks. 

Q. What is a quick setting iron cement ? 

A. Fine iron filings 10 parts; chloride of lime 
3 ; water enough to make a paste. This stands 
steam and is a strong cement. 

CHEMICAL TECHNOLOGY.* 

Q. What methods are employed in bleaching 
oils? 

A. (1). Salt aids clarification. (2). Ordinary 
settling and drawing off the clear liquid, often 
scumming, is often an improvement. (3). Air 
and steam injections often do good. (4). Add 
three quarters to one per cent, of sulphuric acid 
to oil, at 86 deg. Fahr. ; stir three quarters of an 
hour to one hour ; draw off the clear liquid from 
the dark deposit, and wash it with hot water. 
(5). Add two per cent, or three per cent, of quick- 
lime or caustic soda lye, and heat; soaps and 



*See also under Alloys, Coloring Metallic Objects, 
and Paints, Oils, and Varnishes. 



52 Practical Catechism. 

impurities settle. (6). Stir the oil with oil meal 
cake and let it stand. (7). Add one and one 
half per cent of solution of chloride of zinc of 
1.85 specific gravity. (8). Use a centrifugal 
machine to separate the mechanical impurities. 
(9). Add weak solution of permanganate of 
potash. (10). Filtering often helps bleaching 
by removing mechanical impurities which 
would otherwise have to be bleached. 

Q. "What are the principal filtering substances 
used in refining various kinds of oils ? 

A. (1) Carded cotton wadding, (2) cotton wad- 
ding and animal charcoal, (3) dry moss, (4) sand, 
gypsum, and coke, (5) sand and vegetable char- 
coal, (6) carbonized schist and peat, (7) clay 
heated to 200 deg. Fahr.=(93 deg. C), (8) China 
clay and cotton, (9) felt, (10) coke, (11) animal 
charcoal, (12) tow, (13) ground sawdust, (14) 
infusorial earth, (15) ground corn-cobs, etc. 

Q. "What is the material used in loading silks 
to make them heavy ? 

A. A solution of chloride of tin. 

Q. What is the composition of the Swedish 
safety matches that strike only on a special sur- 
face ; and of the material for that surface ? 

A. The "Jonkoping" matches are tipped 
with the following : — 



Practical Catechism. 53 

Parts by weight. 

Potassium Chlorate 40 

Minium 40 

Antimony Tri -sulphide 30 

Potassium Chromate 15 

Gum Arabic , 6| 

The sticking surface is made of 

Ked Phosphorus , 9 

Iron Pyrites 7 

Pulverized Glass 3 

Glue or Gum q. s. 

The pyrites and the glass are finely pulver- 
ized, and intimately mixed. The phosphorus is 
introduced into the gum solution, and the others 
incorporated to form a paste. 

Q. What are the melting points, expansion, 
etc., of paraffine and stearine ? 

A. There are several paraffines or compounds 
containing carbon, hydrogen, and chlorine. 
Cahours and Demargay quote octyl -chlorides 
(C 8 Hi 7 CI.) as having a specific gravity of 0.85 
boiling point 182 deg. C.=359.6 dog. Fahr. 
Fizeau gives its true linear coefficient of expan- 
sion per degree Centigrade as 0.00027.854 at 40 
deg. C.=104 deg. Fahr. 

The paraffine of commerce is quoted as hav- 
ing a specific gravity of 0.870, melting point 



54 Practical Catechism. 

45 C. to 15 deg. C.=113 deg. Fahr. to 149 deg. 
Fahr., boiling point 370 deg. C.=698 deg. 
Fahr. 

Paraffine is a generic term for a series of 
hydrocarbons embracing marsh gas (methylic 
paraffine), hydride of ethyl (ethylic paraffine), 
etc. 

Stearine, on Kopp's authority, has a formula 
C57 Hi 10 6 ; linear coefficient of expansion per 
degree Centigrade 0.0008433 as a mean from 
deg. to 90 deg. C.=32 deg. Fahr. to 194 deg. 
Fahr. ; 0.04963 in melting at 60 deg. Fahr. 

Stearine has a specific gravity (Saussure) of 
1.01 at G=32 deg. Fahr., but between 9 deg. 
and 10 C.=48.2 deg. and 50 Fahr., the same as 
water. Duffy gives melting point 68 deg. C.= 
154.4 deg. Fahr.; solidifying, 65.8 deg. C.=150.4 
Fahr. Stanhorn gives 69 deg. C.=156.2 Fahr.; 
Eedtenbacher and Koppe, 70 deg. C.=158 deg. 
Fahr.; Wardwick 70.5 deg. C.=158.9 deg. Fahr.; 
Kebal 69.2 deg. C.=156.6 deg. Fahr. for the 
purest. (Chevreul gives different figures, but 
his stearine is now known to have been impure.) 

Q. How may ordinary plaster of Paris be 
hardened ? 

A. Mix it with one-sixth of rich lime, recent- 
ly slaked, and finely sifted ; use it like ordinary 
plaster, and then let it absorb all that it can of 



Practical Catechism. 55 

a solution of sulphate of zinc (white vitriol) or 
sulphate of iron (green vitriol, copperas). 

Q. How can linen goods be tested to find out 
if there is jute in them ? 

A. Put a little solution of chloride of lime 
into a saucer and lay in it four or five minutes 
the yarn or cloth to be examined ; then squeeze 
out the solution and put the fabric into a solu- 
tion of ordinary hydrochloric acid ; after a few 
moments take out and wash in plenty of water. 
Then apply a drop of ammonia to the fabric, 
and in case there is a mixture of jute a slightly 
violet red color is immediately imparted. Flax 
and hemp become slightly brown. The red 
coloration, however, does not remain long, and 
the proportion of the jute mixture can only 
be roughly shown. 

Q. What would be a good lining for a sul- 
phuric acid tank ? 

A. Asphalt. Or a box lined with bricks 
soaked in coal tar and the seams and surface 
well payed with the tar. 

Q. How can alcohol be tested for absolute 
freedom from water ? 

A. If it be absolutely free from water, which 
it is not likely to be, it will not be discolored by 
permanganate of potash. If there be the slight- 
est trace of water in it, that water will dissolve 



56 Practical Catechism. 

the permanganate and color the mixture. Abso- 
lute alcohol will soon absorb enough water from 
the air to make it test up as though it were 
diluted with water. 

Q. How can the small bits of refuse material 
which clog up the outlet of a kitchen sink, be 
removed ? 

A. Just before retiring at night, pour into the 
clogged pipe enough liquid soda lye to fill the 
"trap," as it is called — or the bent part of the 
pipe just below the outlet. Be sure that no 
water runs into it until the next morning. 
During the night the lye will convert all the off- 
al into soft soap, and the first current of water 
in the morning will wash it away. 

Q. What is jeweled rouge ? 

A. Red oxide of iron. 

Q. Will ordinary mineral wool attack or cor- 
rode iron ? 

A. It will, under the combined influence of 
heat and moisture. 

Q. How can ink be made, that will copy 
without press or water ? 

A. Add one third glycerine to jet black writ- 
ing fluid. It is best used on glazed paper, and 
excess of fluid on the down strokes or other 
shade lines should be removed with a blotter. 



Practical Catechism. 57 

Q. How can cast iron water pipes be enam- 
elled in the inside ? 

A. The sand core is covered with the enamel 
and the iron then poured in as usual ; the heat 
of the melted metal fuses the enamel right in 
place. 

Q. What is the recipe for enamel for cast iron 
water pipes ? 

A. One is silica 28 parts, calcined carbonate 
of soda 11, and carbonate of lime 6. Another, 
silica 34, carbonate of soda 11, chalk 12, dried 
pipe clay 11. To make the enamel more vitre- 
ous, add boracic acid or oxide of lead. 

Q. How may musk be deodorized tempora- 
rily? 

A. By keeping in contact with lime, with 
milk of sulphur, with sulphide of gold, or with 
syrup of almonds ; but the smell may be restored 
by moistening it with liquid ammonia. 

Q. Give a recipe for a perfume which will 
scent a handkerchief so that it will retain its 
odor even after it has been washed ? 

A. Extrait oVambre has this property and is 
thus made ; — 

Esprit de rose triple J pint. 

Extract of ambergris .... 1 " 

Essence of musk J " 

Extract of vanilla 2 oz. 



58 Practical Catechism. 

coloring metal objects. 

Q. What is a good mixture for browning gun 
barrels ? 

A. 1.5 parts alcohol. 
1.5 chloride of iron. 
1.5 corrosive sublimate. 
1.5 sweet spirits of nitre. 
1 blue vitriol. 
0.75 nitric acid. 

The pieces are to be very carefully cleaned 
with emery and with lime dust, then rusted by 
exposure to the air for twenty-four hours and 
scrubbed with a scratch brush ; then the brown- 
ing composition is to be applied several times, 
an hour apart, and the rust rubbed in with the 
brush, each time before applying another coat. 
When browned enough the surface is washed in 
hot water and when dry cooled, then oiled. 

Q. How may zinc be bronzed ? 

A. Take fifteen parts of verdigris, nineteen of 
cream of tartar, thirty of crystallized soda; 
powder them and dissolve in water. Mix with 
one hundred and sixty parts of pipe clay and 
apply to the zinc objects. 

Q. How may aluminium be whitened ? 

A. Kemove the dirt and grease from the 
plates by dipping in benzine. To whiten the 



Practical Catechism. 59 

metal, leaving on the surface a beautiful white 
mat, the sheet should be first dipped in a strong 
solution of caustic potash. This solution should 
then be dipped in a mixture of concentrated 
acids, two parts nitric acid to one of sulphuric 
acid; then in a solution of undiluted nitric 
acid ; then in a mixture of vinegar and water, 
equal parts ; then washed thoroughly in water, 
and dried as usual in hot sawdust. 

Q. How can zinc be coppered ? 

A. Make a solution of fifteen parts of blue 
vitriol and one of nineteen parts of cyanide of 
potassium ; mix them ; incorporate them with 
one hundred and sixty parts of pipe clay and 
rub the semi-fluid with* a rag upon the zinc ob- 
ject. That will copper it. 

Q. How may brass be reddened ? 

A. By hydrochloric acid, which dissolves the 
zinc. 

Q. How may brass be whitened ? 

A. By ammonia, which takes up the copper. 

Q. How can brass objects be stained golden 
orange ? 

A. By polishing and immersing for a mo- 
ment in a warm solution of neutral acetate of 
copper, then washing in clear water and rub- 
bing dry and bright. 

Q. How may brass be stained dark rich violet ? 



60 Practical Catechism. 

A. By heating to nearly 212 deg. in a bath 
of chloride of antimony. 

Q. How may brass be colored black ? 

A. By a bath of copper nitrate. 

Q. How may brass be given a watered sur- 
face? 

A. By a bath of sulphate of copper (blue 
stone ; blue vitriol.) 

Q. How may brass be colored dark bronze ? 

A. Larkin uses hydrochlorate of copper with 
a little free nitric acid, much diluted. 

Q. How may brass be colored copper-color ? 

A. By hydrochlorate of copper with a little 
much-diluted nitric acid, and a little acetic 
acid. 

Q. How may the patina of antique bronze be 
given to bronze objects ? 

A. By hydrochlorate of copper and diluted 
nitric acid, to which is added ammonia solution 
in large quantities, or sal ammoniac. 

combustion.* 

Q. How much is the draft power of a chim- 
ney influenced by its height ? 

A. It varies as the square root of the height ; 
that is, to get double the draft you must at 



* See also under Fuels. 



Practical Catechism. 61 

least quadruple the height. A chimney with 
double the height will not have more than 1.42 
times the draft, other things being equal. But 
they are hard to get equal. 

Q. How much effect has the friction of the 
chimney walls on the draft ? 

A. It may be said to be equivalent to taking 
from the area a ring two inches wide all 
around ; that is, to a diminution of area equal 
practically to the perimeter times two inches. 

Q. How does the area affect draft ? 

A. The draft is directly as the effective area, 
after the friction ring has been deducted. 

disinfectants and antiseptics. 

Q. Is charcoal a preventer of decay of flesh ? 

A. No ; on the contrary, it hastens decay. 
But it absorbs offensive odors caused by decay. 

Q. What causes the deodorizing properties of 
charcoal ? 

A. Its porosity, its affinity for strong-smelling 
and strongly colored substances, and its prop- 
erty of inducing oxidation of the substances 
which it absorbs. 

Q. How does the so called chloride of lime 
act as a disinfectant ? 

A. The lime combines with acid bodies and 
the chlorine either combines with or decomposes 



62 Practical Catechism. 

the alkaline bodies represented by ammonia. 
At the same time it has the property of oxida- 
tion ; practically burning up many of the offen- 
sive substances evolved in decay. 

Q. How about quicklime as a disinfectant ? 

A. It retards and partially prevents decay ; 
hence is a valuable addition to fresh animal 
matters, but if they have already begun to de- 
cay it at first increases the smell. 

A. How is " Sanitas," or the ordinary com- 
mercial solution of peroxide of hydrogen, pro- 
duced ? 

A. By blowing air through a mixture of 
tnrpentine and water. Part of the oxygen in 
the air combines with the water to form oxi- 
dized water or hydrogen peroxide, while an- 
other part produces, from the turpentine, cam- 
phoric acid. 

Q. Name the principal decay-preventers or 
antiseptics proper ? 

A. Common salt, saltpetre, white arsenic, 
corrosive sublimate, chloride of zinc, chloride 
of iron, carbolic acid, creasote, alcohol, cam- 
phor, the essential oils, and in certain cases, 
quicklime. 

Q. What are the smell-disguisers ? 

A. Most of the strong perfumes, which sim- 
ply mask over a bad smell. 



Practical Catechism. 63 

Q. What are the smell-removers or deodor- 
izers ? 

A. Among them may be named charcoal, 
peat (fresh and charred), clay (burned, un- 
burned, or smother-burned along with vegetable 
matter), and other porous substances. 

Q. What are the principal smell-destroyers 
or disinfectants ? 

A. Those which not only absorb and remove 
evil smells, but decompose and change them, 
and thus remove them, comprise among others 
nitric oxide, sulphurous acid, chlorine, the 
chlorides of lime, zinc, and iron, the sulphate 
of iron, iodine, hydrogen peroxide, permangan- 
ate of potash, and quicklime. Carbolic acid 
and creasote unite to a remarkable extent the 
characters of antiseptics and disinfectants. 

fastenings.* 

Q. What should be the thickness of trenails ? 

A. One-third the thickness of the planks 
which they unite. 

Q. What are the best materials for trenails ? 

A. Oak and locust. 

Q. What is the resistance to drawing of a 
good sixpenny nail ? 



* See also under Cements. 



64 Practical Catechism. 

A. Those 2J inches long and weighing 73 to 
the pound, require if driven one inch, 187 
lbs. ; 1 \ inches, 327 lbs. ; two inches, 530 lbs., 
into pine across the grain. 

Q. What is the resistance of a sixpenny nail 
driven into different woods ? 

A. Driven an inch into pine, across the 
grain, 187 pounds ; oak, 507 ; elm, 327 ; pine 
with the grain, 87 ; elm with the grain, 257. 

Q. How about the resistance to drawing of 
spikes in different woods ? 

A. Elm and ash will hold a spike about two- 
thirds as well as oak or beach, and a third bet- 
ter than chestnut ; soft maple and sycamore are 
four-fifths as effective as chestnut, two-fifths as 
good as oak and beech, and a half better than 
hemlock. 

Q. How about the force required to drive 
nails ? 

A. It takes in soft woods about 20 per cent, 
more force to drive by steady pressure than to 
draw. 

Q. Why are the fastenings of wooden ships 
often made of copper ? 

A. Because it does not oxidize greatly by the 
action of the wood through which it passes, and 
its oxide does not injure the wood. 



Practical Catechism. 



65 



Q. What is the absolute strength of a well 
glued joint ? 

A. As given in this table : — 





Pounds per square inch. 




Across the grain 
end to end. 


With the grain. 


Beech 

Elm 


2133 
1436 
1735 
3149 
1422 


1095 
1124 


Oak 


568 


White wood . . 
Maple 


341 

896 



Q. What is the composition of marine glue ? 

A, India rubber, 1 part ; coal tar naphtha, 8 
to 12 ; shellac, 15 to 20 ; melted together and 
used hot. 

Q. How can waterproof glue be made ? 

A. Boil 8 parts of common glue with 30 of 
water, until a strong solution is obtained ; add 
4J of boiled linseed oil, aud let the mixture 
boil two and a half minutes, stirring constantly. 

FLUXES.* 

Q. What is the theory on which a flux acts ? 

A. That it often happens that two substances 
which have a powerful affinity for each other 
will unite chemically when brought into con- 



* See also under Foundry Practice. 



66 Practical Catechism. 

tact, and will form a new compound which 
melts at a lower temperature than that at 
which either will melt alone. 

Q. What will flux silica? 

A. Potash, soda and lime. 

Q, What will flux iron ? 

A. Borax will unite with the oxide of iron 
to form a fusible glass, so the blacksmith uses it 
in welding iron. Quartz sand will do the same 
thing ; so will fluor spar. 

Q. How can the practically infusible metal 
iridium be cast ? 

A. By using phosphorus as a flux ; heating 
the ore to whiteness and then adding the phos- 
phorus. 

Q. How may solid copper castings be made ? 

A. By using as a covering to the crucible, horn 
filings instead of the usual charcoal or guano. 

Q. How can sound German silver castings be 
made? 

A. By the use of borax or of glass as a flux. 

FOODS* 

Q. What are the various kinds of flour which 
produce the various qualities demanded in 
bread ? 



*See also under Sugars. 



Practical Catechism. G7 

A. The flours best adapted for blending, 
whether British and Irish or foreign made, will 
be for — 

Size of Loaf. — Kussian and American spring 
straight grades. 

Size and Quality. — Russian, American spring 
and winter high grades, with an admixture of 
fine English high grades. 

Sweetness. — Hungarian, Polish, American 
spring high grades ; English. 

White Color. — Oregon, Californian, Chilian, 
American winter, and white English — all high 
grades. 

Yellow Color. — Walla Walla, Kubanka, 
hard Chilian ; some varieties of English. 

Size and Cheapness. — Low-grade American 
spring (bakers'), common Russian, Indian and 
red English. 

Cheapness. — Lowest grade American, Italian, 
Persian, common English. 

Q. What will make the most bread, hard 
spring wheat, or soft winter wheat ? 

A. The hard spring wheat flour, if properly 
milled, contains the most gluten, hence will ab- 
sorb the most water and make the most bread, 
if properly doughed and baked. 

Q. What is the test of a well-milled flour ? 

A. Throw some of it against a rough wall. 



68 Practical Catechism. 

Of several samples thrown against the same 
wall, the one of which the most sticks will be 
the strongest and sharpest. Take a little in the 
hand, and shut the hand upon it. Its sharpness 
and strength are to some extent indicated by the 
sharpness with which it takes the impression of 
the lines of the hand and the cracks between 
the fingers. Dough up some of it. The tacki- 
ness and length of the string to which the 
dough can be pulled out, and the amount of 
resistance which it offers to being pulled out, 
are in great measure indicative of strength in 
the flour. 

Q. How can stale bread be perfectly restored 
to freshness ? 

A. By putting it in a closely-covered tin ves- 
sel, and exposing for half an hour to a tempera- 
ture not exceeding boiling water. The water 
which is absorbed in becoming what is known 
as " stale " will be driven off. 

Q. How much water will well baked wheaten 
bread contain ? 

A. After baking, about forty per cent. 

Q. How much water will good flour take up 
in doughing ? 

A. One hundred pounds of fine wheaten flour 
will take up forty-five of water. 



Practical Catechism. 



69 



Q. What are the relative values of various 
foods as productive of force, when oxidized in 
the body ? 

A. 

Cabbage 1. 

Carrots 1.2 

Egg (white) 1.4 

Milk 1.4 

Apples 1.5 

Ale 1.8 

Fish 1.9 

Potatoes 2.4 

Porter 2.6 

Veal 2.8 

Mackerel 3.8 

Ham (lean) 4. 

Bread (crumb) 5.1 



Egg, yolk 7.9 

Sugar 8. 

Isinglass 8.7 

Eice 8.9 

Pea meal 9. 

Wheat flour 9.1 

Arrowroot 9.3 

Oatmeal 9.3 

Cheese 10.4 

Cocoa 16.3 

Butter 17.3 

Fat of beef. 21.6 

Cod liver oil 21.7 

Egg (hard boiled) . 5.4 

Q. What kind of food is most capable of 
sustaining life, weight for weight ? 

A. The chick pea, which is selected by trav- 
ellers about to cross the deserts. 

Q. What is the advantage of cooking in oil 
rather than boiling in water ? 

A. In the first place the oil boils at a much 
higher temperature than water does, and hence 
cooks the substances more thoroughly ; in the 
second place there are many substances which 



70 Practical Catechism. 

are very much improved by having the oil enter 
into them as a nutriment. 

Q. How much do beef and mutton lose in 
cooking ? 

A. Fresh beef and mutton when moderately 
fat, suffer on an average about these losses : — 



In boiling. 



In baking. 



In roasting. 



4 lbs. of beef lose 1 lb. 
1 " mutton " 14 oz. 



1 lb. 3 oz. 
1 lb. 4 oz. 



1 lb. 5 oz. 
1 lb. 6 oz. 



Q. Why is it that so much is lost in baking 
and in roasting ? 

A. Partly because the water is evaporated 
and partly because the fat is melted out. 

Q. Should meats be roasted and baked by a 
quick or a slow fire ? 

A. By a quick fire, in order that the outside 
pores may be closed and the juice prevented 
from escaping. 

Q. In boiling meats should they be put at 
first into cold or into hot water ? 

A. Into boiling water, in order that their 
pores may be closed and the juices not leached 
out. 

Q. In making beef tea should the shreds of 
meat be put into hot or into cold water ? 



Practical Catechism. 71 

A. Into cold, to commence with, in order that 
the juices may best be extracted. 

Q. What is the effect of salt upon meat ? 

A. It causes the fibres to contract, the meat 
to lessen in bulk, and the juice to flow from its 
pores. Thus it diminishes the flavor and pre- 
vents the entrance of the air which would cause 
decay. 

Q. What classes of fat meat will keep best by 
salting ? 

A. Those with hard fat. 

Q. How may hard fat be produced ? 

A. By giving dry food some time before kill- 
ing. 

Q. What are the relative volumes and meas- 
ures of various solids and liquids used in every 
day life ? 

A. Solids — Wheat flour, one pound is one 
quart ; Indian meal, one pound two ounces are 
one quart ; butter, when soft, one pound is one 
quart; loaf sugar, broken, one pound is one 
quart ; white sugar, powdered, one pound one 
ounce are one quart; best brown sugar, one 
pound two ounces are one quart ; eggs, ten weigh 
one pound ; flour, eight quarts are one peck 
and four pecks are one bushel. Liquids — Six- 
teen large tablespoonfuls are one-half pint ; 
eight large tablespoonfuls are one gill ; four 



72 Practical Catechism. 

large tablespoonfuls are one-half gill ; two gills 
are one-half pint ; two pints are one quart ; four 
quarts are one gallon. A common sized tumbler 
holds one-half pint ; a common sized wineglaas 
holds one-half gill ; a teacup holds one gill ; a 
large wineglass holds two ounces ; a tablespoon- 
ful holds one-half ounce ; forty drops are equal 
to one teaspoonful and four teaspoonfuls are 
equal to one tablespoonful. 

FOUNDRY PRACTICE.* 

Q. What determines the strength of a casting 
as much as the quality of the metal of which it 
is made? 

A. Its soundness. 

Q. Other things being equal, suppose an iron 
casting is desired, having one end heavier than 
the other, which end should be cast uppermost 
and why ? 

A. The heavy end up, because it can be fed 
after the latter part has set. If the heavy part 
is down the top will set and the lower part can- 
not be fed. 

Q. Suppose it is absolutely necessary that the 



*See also under Alloys, Iron and Steel, Metals, 
Strength of Materials, etc. 



Practical Catechism. 73 

large part shall be at the bottom, how can it be 
fed to insure soundness ? 

A. By having an independent feeding-head ; 
or by enlarging a section of the top part. 

Q. Are fillets always a source of strength ? 

A. No ; a fillet may be a source of weakness 
in a casting, because it may require to be fed 
from the main body of the casting and thus 
cause flaws. 

Q. When balls are cast without feeding, 
where are they apt to be the least dense ? 

A. In the center. 

Q. How is it with fed balls? 

A. They will be denser in the center than in 
their outer portions. 

Q. Which will be the stronger, iron castings 
poured hot or those poured with dull metal ? 

A. Those poured hot, as proved at Pratt & 
Whitney's foundry by Gardiner. 

Q. How may the # tendency of cast iron to 
pour with the dirt at the top be counteracted in 
casting ? 

A. By a skimming core; the metal being 
first poured in a basin with a bridge under 
which it must pass in order to get to the riser 
from which the mold proper is filled. The 
metal which passes under the bridge will be free 
from dross or scum. Another way is to have a 



74 Practical Catechism. 

skimming gate, the metal being poured down 
one leg of a U, and drawn from the bottom of 
the other leg ; the hole from which it is drawn 
at the bottom of the second leg being smaller 
than the second leg, so that the tendency will 
be to keep the latter full. This is practi- 
cally a skimming core in section. The horizon- 
tal cross section of such a skimming arrange- 
ment should be /-shaped ; that is, the passage 
should leave one leg at a tangent in the direc- 
tion of the hands of a watch, and enter the 
other at a tangent in a direction contrary to the 
hands of a watch. This will set up a whirling 
action in the metal which will tend to skim it. 

Q. What rule may be laid down for casting 
where it is reasonable to expect dirt or porous- 
ness? 

A. West says to make that section thicker or 
heavier than the design would call for, in order 
to counterbalance the weakening effect caused 
through the mingling of dirt or impurities with 
the iron. 

Q. What is the difference between shrinkage 
and contraction in castings ? 

A. Shrinkage occurs when the metal is 
liquid ; contraction, after the casting is made 
and the metal solid. Shrinkage can be pre- 
vented; contraction cannot. But the term 



Practical Catechism. 75 

shrinkage is generally used to indicate the dif- 
ference in size between the pattern and the 
casting. 

Q. Is it possible for a cylinder cast horizon- 
tally to be as sound as one cast vertically ? 

A. No ; dirt will be caught and held by the 
under side of the centre core and also in the 
cope. 

Q. What is one advantage of using hot iron 
instead of dull ? 

A. It will float dirt and let it rise up through 
it more quickly than dull. 

Q. What may be said of casting cylinders 
from the top and from the bottom ? 

A. Those cast from the top usually have a 
rougher skin than those poured from the bot- 
tom, by reason of the rising metal rubbing 
against the mold surface. They are also more 
apt to be scabbed and cut than those poured 
from the bottom; but they will as a general 
rule finish up clean. 

Q. Should chaplets ever be set against the 
center core of a cylinder ? 

A. No ; they are likely to produce blow-holes 
in the bore if thus set. 

Q. Should chaplets be set against a valve 
face? 

A. No ; because cylinder-iron is usually eas- 



76 Practical Catechism. 

ily chilled, and the chaplets tend to chill it and 
make it hard to finish. 

Q. What should be done in fitting up old pits 
for drying molds, if there is not good natural 
draught ? 

A. A blast pipe should be laid all around the 
bottom and connected with a fan or blower. 

Q. What gives the most trouble in making 
thin cores ? 

A. Eodding and venting them. 

Q. What is the principal cause of gases from 
cores ? 

A. The materials from which they are made. 

Q. What material causes the most gas in 
core making ? 

A. Flour. 

Q. What makes but little gas ? 

A. Resin. 

Q. What are the disadvantages of resin for 
core making ? 

A. It requires to be powdered ; is difficult to 
handle; resin cores cannot be handled when 
hot and are not so reliable for heavy castings ; 
besides which they cannot be pasted together as 
flour cores can be. 

Q. What is the principal advantage of resin 
for cores, besides their producing but little 
gas? 



Practical Catechism. 77 

A. That they do not require to be blacked as 
flour cores do. 

Q. What is the advantage of using fine sand 
for cores ? 

A. That it gives smooth castings. 

Q. What is the disadvantage ? 

A. That if too fine the gases cannot get out. 

Q. Should cores be dried in the air ? 

A. No ; they should be put at once into the 
oven after making. Air-dried core surfaces 
are apt to crumble. 

Q. What about the amount of water to be 
used in core-making ? 

A. The wetter the sand, the less flour or 
resin that is needed ; but if it is too wet, small 
cores will stick to the boxes and large ones will 
be liable to sag or to crack. 

Q. How can the quantity of flour be less- 
ened ? 

A. By using boiled flour. It is better if all 
the water that is used is boiled with the flour. 

Q. For setting cold cores in green-sand molds, 
what will lessen the danger of chilling or gen- 
erating steam ? 

A. Working the flour with machinery oil. 

Q. What is the advantage of long runners ? 

A. The longer the distance through which 
iron is made to travel before it can enter the 



78 Practical Catechism. 

mold, the better the chances for catching and 
preventing the dirt from getting into the mold. 

Q. What is a good mixture for sand for mold- 
ing purposes ? 

A. Twenty parts of fine sand, one of litharge, 
mixed together and sifted through a fine sieve, 
then enough boiled linseed oil added to make to 
the temper of boiling sand such as would be 
used for molding. The mixture is rammed as 
one would ram molding-sand, and the board 
then left to dry for twelve hours. The oil gives 
firmness to the sand, and the litharge dries the 
oil. 

Q. What is the reason that foundries do not 
use more green-sand cores for pipe work ? 

A. They generally require more or less rig- 
ging. 

Q. What is their advantage? 

A. They usually give smoother and truer 
holes than dry-sand cores do, and generally 
thinner castings may be made with them. 

Q. What is the objection to pounding down a 
pattern as against tucking it up ? 

A. Pounding down causes a mold to be the 
reverse of what it should be, and abuses the 
pattern. 

Q. What is the rule for flask weights ? 

A. Multiply the lifting area by the height of 



Practical Catechism. 79 

head and the product by the weight of a cubic 
inch of cast iron (.26 lbs.) 

Q. What is the lifting pressure of a core ? 

A. The number of pounds of metal its body 
displaces, less the weight of the core itself. 

Q. What is a good thing to use where it 
takes a long time to slick a blacked green-sand 
mold, where the blacking becomes sticky ? 

A. The dust of silver lead. 

Q. What is the objection to soapstone as a 
mold-facing ? 

A. The light color or skin that it gives to the 
castings. 

Q. What sort of iron should be used for burn- 
ing castings ? 

A. That which is very soft, in order that it 
will not chill readily ; and the temperature 
should be as high as possible. 

Q. What are the advantages of coke over 
coal in melting iron ? 

A. It melts faster than coal, requires less 
blast pressure, and is cheaper ; besides which 
some claim that it contains less impurities and 
will make softer castings. The last point is 
open to doubt. 

Q. In what is coal superior to coke in melt- 
ing? 

A. In the ability to melt very heavy masses. 



80 Practical Catechism. 

Thus Pratt & Whitney melted a 6000 lb. 
block by using coal ; and could not have done 
this by using coke. 

Q. What was the order of procedure in this 
case of melting a three-ton block ? 

A. 2000 lbs. of coal were put in as a bed, 
and the three-ton block put on this; then 
around this was put 400 lbs. of coal and the fire 
started ; then after well going through were put 
in four charges each of 500 lbs. of coal and 4000 
lbs. of scrap and pig. The first 500 lbs. of coal 
were put on the 6000-lb. block, which was 
thus buried in 2900 lbs. of coal. 

Q. What is the disadvantage of carrying fuel 
economy too far in iron-molding ? 

A. There is liability of the iron coming down 
so dull that castings will be lost and the ladles 
bunged up. 

Q. What is one of the principal advantages 
of mixing coal with coke ? 

A. Lengthening the life of the heat ; doing 
clean cupola work, and producing hot iron. 

Q. Which takes the longer to kindle in cu- 
pola work, coal or coke ? 

A. Coal. 

Q. How long should be allowed for kindling ? 

A. Just enough to have the fuel all on fire 
before any iron is charged. 



Practical Catechism. 81 

Q. How about the blast required for coke, as 
compared with coal ? 

A. Coke requires about one-third less pressure 
than coal. 

Q. What is the result of using too strong a 
blast? 

A. Having to re-line the cupola too often ; 
difficulty in obtaining good clean iron ; difficulty 
in running long heats. 

Q. What is the rule for the area of tuyeres of 
melting cupolas ? 

A. The maximum area for the sum of all the 
tuyeres should be twenty-five per cent, of the 
average area of the cupola ; the medium, one- 
ninth the area ; the minimum, one-twentieth the 
cupola area. 

Q. What is the idea of mixing steel with cast 
iron? 

A. To add strength to the iron or increase 
the depth of its chill. 

Q. On what will the maximum amount of 
steel (or of wrought iron) which may be added 
to cast iron, depend ? 

A. Upon the heat of the iron and upon what 
it is to be poured into ; also upon what grades 
of steel and of cast iron are used. Low carbon 
cast iron calls for low carbon steel. 



82 Practical Catechism. 

Q. What is desirable in making castings of 
mixed steel and cast iron ? 

A. To get as much of the mixture as possible 
in a large ladle and stir it with a wrought iron 
rod. 

Q. How may steel be melted in an ordinary 
cupola ? 

A. By following up after cast iron ; waiting 
until the cast iron part is all gone and then 
charging in steel and not running out any steel 
until the last has been charged. 

Q. What are the shrinkage rules used by 
leading foundries ? 

A. The I. P. Morris Co., Phila., gives the 
following as the shrinkage per foot : 
Loam castings, iron, large 1-1 6" 
Green-sand castings, iron, large 1-12" 
Dry -sand castings, iron, large 1-1 6 7/ 
Brass castings, scant J" 
Gunmetal castings, full \" 
Copper castings 1-1 6 7/ 

For computing the weight of castings from 
pine patterns, this company uses for small or- 
dinary iron castings the multiplier 16 ; ordinary 
brass pieces, 20. 

The Betts Machine Co., Wilmington, Dela., 
says : " Ordinary green-sand work shrinks from 
1-10" to Y f per foot. There is no rule that we 



Practical Catechism. 83 

know of that will suit all classes of work. The 
founder must be the judge and proportion the 
shrinkage to the work. We make green-sand 
that does not shrink at all ; and again, on other 
work, we allow 1-1 6" to the foot. 

The following figures are given in a technical 
journal : 

In locomotive cylinders, one-tenth of an inch 
in a foot; pipes, one-third of an inch in a 
foot; girders, beams, etc., one-third of an 
inch in fifteen inches ; engine beams, connect- 
ing rods, etc., one-third of an inch in sixteen 
inches ; large cylinders, say seventy inches in 
diameter, 10 feet stroke, the contraction of 
diameter, three-eighths of an inch at top ; 
ditto, one-half inch at bottom ; ditto, in length, 
one-third of an inch in sixteen inches ; thin 
brass, one-third of an inch in eight inches; 
thick brass, one-third of an inch in ten inches ; 
zinc, five-sixteenths of an inch in a foot ; lead, 
the same ; copper, three-sixteenths of an inch 
in a foot ; bismuth, five-thirty-seconds of an 
inch in a foot ; tin, one-quarter of an inch in a 
foot. 

Q. " How can I get dead smooth iron cast- 
ings?" 

A. The production of smooth castings may be 
greatly facilitated by the use of properly pre- 



84 Practical Catechism. 

pared, good quality plumbago or black lead as 
a blackening or facing. 

I had occasion several years ago to make a 
lot of hose-couplings, in which, instead of the 
usual "false back" system of making female 
couplings for 2\" hose with a 2J 7/ screw 
thread, I cast the head first with a square inter- 
nal groove and a fillet, and then run the shank 
with two fillets and a groove, thus casting the 
swivel joint without any separate backing piece 
to be pinned on. I succeeded excellently well 
by using black lead in the mold. My experi- 
ence in this connection was recalled by the fol- 
lowing paragraphs in the circular of a graphite 
manufacturer : 

Something is needed that will prevent the 
sand of the mold from being burned by the 
molten metal; that will cause the casting to 
* peel ; readily ; that will deliver the casting 
smooth from the mold, with a l slick ' surface 
and a bright color. 

" To do this the blackening used must be re- 
fractory, something that will neither burn nor 
run before the molten metal at the time of 
pouring ; it must adhere firmly to the surface of 
the mold, and part well, or * peel ' readily 
from the casting; it must admit of being 
smoothed or ' sleeked ' in the finishing of the 



Practical Catechism. 85 

mold ; finally, it must give the casting a uni- 
form bright color. 

" Plumbago (or black lead) blackening or 
facing, if of good quality and properly prepared, 
will do all this. It will do it both well and 
cheaply, as enough of the expense of dressing 
castings will be saved to more than pay for the 
blackening." * 

Q. What will make a good mold for steel 
castings ? 

A. Pure silica, held together by a slight ad- 
mixture of glue, water and rye flour. As this 
is very porous, there should be used a facing of 
silica in very fine powder. 

Q. In making malleable iron, which is the 
best to use ; a reverberatory furnace or a cu- 
pola? 

A. A reverberatory furnace uses more fuel 
than the cupola, but gives purer metal ; also, if 
the pig contains too much carbon it may be ox- 
idized out in the furnace. 

Q. How may the oxygen taken out of the 
iron scales in making malleable iron castings, 
be restored? 

A. By grinding them and wetting them with 
a solution of sal ammoniac ; or by wetting them 
with water, stirring, and drying upon the top of 
the annealing furnace. 



86 Practical Catechism. 

Q. Can malleable iron castings be made by 
any other method than that of annealing grey 
iron castings or that of adding aluminium to the 
melted metal ? 

A. By adding to ten pounds of molten iron in 
the crucible of a brass furnace two ounces of 
fluoric acid and one ounce of saltpetre. After 
casting, keep at a red heat for three or four 
days in iron boxes, in the furnace. 

Q. For making malleable iron castings what 
class of iron is best ? 

A. Charcoal iron of the best quality, free 
from sulphur and phosphorus. 

Q. How are the castings treated in order to 
make them malleable ? 

A. They are embedded in oxide of iron — usu- 
ally in the form of hematitic ore — or in perox- 
ide of manganese ; and highly heated. 

Q. Will malleable iron castings weld ? 

A. No. 

Q. What takes place during the heating ? 

A. Nearly all the carbon is absorbed by the 
oxide of iron or of manganese. 

Q. How is the temperature of the molten 
iron determined ? 

A. By withdrawing a drop on an iron rod ; 
if it burns on exposure to the air it is right and 
must be poured quickly. 



Practical Catechism. 87 

Q. How else may malleable iron castings be 
made? 

A. By melting together selected cast iron and 
good wrought iron. This is really a steel-mak- 
ing process. 

FUELS.* 

Q. How can sulphur be removed from coke 
in the process of manufacture ? 

A. By the addition of salt to the coal in the 
coking process, double decomposition produces 
volatile compounds of sulphur and chlorine. 

Q. What is the best age for wood from which 
to make charcoal ? 

A. About twenty years. Decay should not 
have commenced before charring. 

Q. What effect has the temperature of pre- 
paration of charcoal upon the temperature of 
combustion ? 

A. That prepared at a low temperature is 
more combustible than that made at a high 
temperature. Thus while that prepared at 300 
deg. Fahr. ignites at 250 deg., that made at 500 
deg. will ignite at 650 deg. 

Q. Has this any practical bearing upon the 
liability of steam pipes to set wood on fire by 
charring ? 



* See also under Combustion, Foundry Practice, etc. 



88 Practical Catechism. 

A. Yes. The relation between the tempera- 
tures of proportion and ignition of charcoal is 
such that the two will never coincide below 500 
deg. Fahr. — so it is not likely that wood will be 
set on fire by the same pipes which char it. 

Q. What are the advantages claimed for the 
use of liquid fuel ? 

A. Reduction of weight of about 40 per cent. ; 
reduction of bulk of 36 J per cent. ; reduction of 
firemen or stokers of 75 per cent. ; prompt kind- 
ling of fires and ease of instantaneous extin- 
guishment. 

Q. What are the disadvantages ? 

A. Liability of explosions by vapors from 
the fuel, loss of fuel by evaporation ; unpleasant 
odors of all the liquid fuels likely to be used ; 
comparatively high price of the liquids. (This 
last varies and may vanish.) 

Q. In an ordinary reheating furnace what is 
the proportion between coal and iron ? 

A. One ton of coal heats If tons of iron, and 
produces only 1-23 of the maximum theoretical 
effect. 

Q, How is the proportion in melting steel in 
pots? 

A. One ton of steel takes 2 J tons of coke to 
melt it ; which is only about 1-70 of the maxi- 
mum theoretical effect. 



Practical Catechism. 89 

Q. To what temperature are the gases of 
combustion reduced by the use of a proper re- 
generator ? 

A. To about 300 deg. Fahr. 

Q. What are the advantages of the regenera- 
tive furnace in melting iron and steel ? 

A. Besides economy in fuel, the most intense 
heat can be obtained with a moderate draft, so 
the gases are free from dust when they reach 
the hearth, and do that cut it away. The tem- 
perature is adjustable to any degree of heat or 
of oxydizing or deoxidizing power; and the 
maximum temperature is practically only lim- 
ited by the resisting power of the walls and 
linings. 

Q. What is the maximum temperature attain- 
able in the regenerative furnace ? 

A. The theoretical limit is near 4500 deg. 
Fahr. (2482 deg. C.) where the action of chemi- 
cal affinity is stopped by the intensity of heat 
repulsion. 

Q. How may economy in steel-melting be 
reached ? 

A. By increase of temperature. 

Q. What is the only bar to this ? 

A. Lack of durability of furnaces. 

Q. Is the heating effect of fuel greater when 
it is mixed with the material to be melted or 



90 Practical Catechism. 

when it is worked separatively as in the regen- 
erative furnace ? 

A. Greater where it is mixed with the sub- 
stance to be reduced. Thus large iron blast 
furnaces utilize 70 to 80 per cent, of the heat 
actually generated ; the Siemens and Ponsard 
furnaces, only 15 to 20 per cent ; while in the 
ordinary wind furnace, only 1.7 to* 3 per cent, is 
utilized. 

Q. What is the effect of exposure to the 
weather upon coal ? 

A. It absorbs oxygen, and the slow combus- 
tion lessens its heating powers. Also, freshly 
mined coal may give out hydrocarbons which it 
would be best that they retain. Besides this, 
the hydrocarbons are liable to cause explosions 
if mixed with ordinary air. 

Q. To what is the combustible value of an- 
thracite coals practically proportioned ? 

A. To the percentage of carbon. 

Q. " How is the volume of chimney gases 
calculated, when you know what there is in the 
coal ? That is, suppose we know that there is 
such and such a per cent, of carbon, and of hy- 
drogen, and of all the rest, and can regulate the 
air supply so as to give them just enough air, 
and no more ? " 

A. It sometimes is a long and tedious calcula- 



Practical Catechism. 91 

tion, because allowance must be made for the 
change of volume of the air and gases, where 
you cipher up that a given number of cubic feet 
are admitted. But by weight, we are certain of 
this : 

One lb. carbon and 2.66 lbs. oxygen, make 
3.66 lbs. of carbonic acid. 

One lb. hydrogen and 8 lbs. of oxygen, make 
9 lbs. of steam or of water. 

One lb. of sulphur and 1 lb. oxygen, make 2 
lbs. of sulphurous acid. 

A. Neglecting the sulphur which it contains, 
allow for every pound of hydrogen 457 cubic 
feet of air at 62 deg. Fahr. ; for every pound of 
carbon, 152. Thus if 100 lbs. of coal contain 4 
of hydrogen, 20 of volatile carbon and 60 of 
fixed carbon, we have as follows : 
,. r . ., , Hydrogen.. 4X457=1828 cu. ft. 
( ^° latlle) Carbon... 20X152=3040 
(Fixed) Carbon. . . . 60x152=9120 



13988 cu. ft. 
required as a minimum to burn the 100 lbs. 
completely; or for one pound practically 140 
cubic feet, weighing 10.7 lbs. 

Q. How is the volume of chimney gases to be 
determined ? 

A. The weight, or else the volume at 62 deg., 



92 Practical Catechism. 

must first be found, and then the volume re- 
duced to the temperature of the escaping gases. 
Allowing an excess of air equal to the minimum 
actually required for 1 lb. of coal, we have 
in round numbers, at 62 deg. Fahr., the follow- 
ing volumes for one lb. of coal perfectly 
burned : 

cu. ft. lbs. 
Gaseous products of combustion, 150=12 
Surplus air, 140=10.7 

Total escaping gases at 62 deg., 290 22.7 

These 290 cubic feet would at 500 deg. Fahr. 
occupy about 533 cubic feet ; the minimum of 
150 cubic feet at 62 deg. making about 276 cubic 
feet at 500 deg. Fahr. 

Q. What is the heating power of wood as 
compared with that of coal, pound for pound ? 

A. About 54 per cent., or a little more than 
half, for dry wood. If there is 25 per cent, of 
water then this will be reduced to f of 54, which 
is 40J per cent., which might be taken as the 
average for ordinary wood — say 40 per cent, 
that of coal. 

Q. What is the rule for finding the number 
of cords of wood which should be equal to a cer- 
tain number of tons of coal ? 

A. A cord of pine cut up and piled averages 



Practical Catechism. 93 

21 lbs. per cubic foot in the cord of 128 cubic 
feet ; that is 2700 lbs. per cord. If this is esti- 
mated at 25 per cent, water it will be equal to 
2700x0.40=1080 lbs. of coal, which is between 
half a long ton and half a short ton. If per- 
fectly kiln-dried after measuring it would weigh 
only 2025 lbs., or a trifle over a short ton, and 
would have a heating power equal to about 
1080 lbs. as before. 

Q. Which has the most carbon, anthracite or 
bituminous coal ? 

A. Pennsylvania anthracite has 88.54 per 
cent, of fixed carbon, and Pennsylvania bitu- 
minous, 73.21 per cent. ; Western bituminous, 
57.42 per cent. The Pennsylvania coal has 3.97 
per cent, of volatile matter (not water) which 
contains some carbon; the Pennsylvania bitu- 
minous, 15.11 per cent ; and the Western bitu- 
minous, 32.68 per cent. 

Q. " Has anthracite coal ever been ' coked ' in 
practice, to use in iron-making or under a 
boiler, or work like that ? " 

A. Anthracite has been used as the basis of a 
good coke, 60 per cent, of anthracite and 35 per 
cent, of bituminous coal were mixed with 5 per 
cent, of hard pitch. They yielded 80 per cent, 
of hard steel-gray coke, which burned in a com- 



94 Practical Catechism. 

mon fire, or in a blast furnace, without any 
signs of crumbling. 

Q. How many horse-power ought we to get 
by the perfect combustion of one pound of coal 
in an hour ? 

A. Supposing one pound of coal to give out in 
its complete and perfect combustion, to carbonic 
acid, 14,000 heat units, this is the equivalent of 
14,000X772=11,008,000 foot lbs.; and this 

11,008,000 

equals =5.56 horse-power if exerted 

33,000X60 

in one hour. If exerted in a minute, it would 
yield 

11,008,000 

=333.6 horse power. 

33,000 

A. How can heavy oil best be used as fuel ? 

A. Dr. Werner Siemens uses in some of his 
copper mines in the Caucasus boilers heated by 
a heavy oil, the residue of the distillation of 
petroleum, brought by rail from Bakou. 

The best results are given by drafting the 
oil by means of a steam jet into the centre of an 
interior fire-box of large size, so that the flame 
shall not touch the walls of the boiler ; then he 
returns the flame by a number of tubes of small 
diameter. Thus the combustion is complete, 



Practical Catechism. 95 

and the expense for combustible is less than by 
burning wood, although the establishment is in 
the middle of a forest. 

Q. What is the scientific method of determin- 
ing the exact heating power of fuel ? 

A. " Mr. William Thomson, in a paper read 
before a Manchester, England, scientific society 
a short time since, described an apparatus re- 
cently devised by him to determine the heating 
power of different coal samples. The method 
which he follows consists in burning the coal in 
oxygen. The apparatus, briefly described, is 
made up of a stand furnished with four upright 
brass springs. There are strips of brass fixed to 
the stand at the bottom and curved upward and 
inward. In this stand is fitted the bowl of an 
ordinary clay tobacco pipe rather less than J 
inch internal diameter by 1J inches long. This 
is used as a stand for a small platinum crucible, 
I inch diameter by 1J inches long, because the 
clay is a non-conductor of heat, and would not 
injure the platinum when heated to redness. 
Into this platinum crucible is introduced 1 gram 
of coal in a fine state of division, which is ig- 
nited, after being placed on its stand, by a fuse, 
and the whole covered by an inverted wide 
glass test tube, 6 inches long by 1 J inches diam- 
eter, to the bottom of which was attached a 



96 Practical Catechism. 

piece of narrow tubing, 1 inch long by f inch in 
diameter. Over this tube is drawn a piece of 
india-rubber tubing, the free end of which is 
turned over on itself, and through this rubber is 
passed a glass or thin copper tube (preferably 
the latter) terminating with a stop cock. The 
fuse is prepared by soaking two or three strands 
of ordinary lampwick in nitrate of potash solu- 
tion and drying. About f inch of this fuse is 
placed upright in the mixture. 

When the fuse is ignited the mouth of the 
test tube is pushed over the brass springs, thus 
inclosing the platinum crucible containing the 
coal on the diving-bell principle, and the whole 
is then sunk into a cylinder containing either 
1934 or 2000 grams of water, the temperature 
of which has previously been taken by a delicate 
thermometer. A stream of oxygen from a gas- 
holder or gas-bag is then allowed to flow slowly 
through the test tube downward, making its es- 
cape at the mouth and bubbling through the 
water. It is necessary to commence the com- 
bustion by having the movable tube which pen- 
etrates the bottom of the test tube drawn well 
up, so as to have a complete atmosphere of ox- 
ygen in the test tube until most of the volatile 
matter of the coal is consumed. The movable 
tube is then gradually pushed down till it comes 



Practical Catechism. 97 

to the mouth of the platinum crucible, a slow 
circular movement is then given to it by the 
hand till the whole of the fixed carbon of the 
coal is consumed, which is rapidly done under 
the stream of oxygen impinging on it. The ash 
is then left as a number of fused globules, many 
of them adhering to the crucible, having been 
completely fused by the intense heat of the 
combustion. The water is then allowed to enter 
the tube and come in contact with the hot cruci- 
ble and tobacco-pipe support and entrance tube 
for the gas to abstract the heat left in them. 
The whole of the water is then well mixed and 
the temperature again taken, the difference be° 
tween the two temperatures being the heat 
given to the water by the combustion of the 
coal. Mr. Thomson has found that the temper- 
ature of the water is practically not altered by 
passing about 3 gallons of air or oxygen through 
it, that being in excess of the quantity required 
to burn the coal, between 1 J and 2 gallons being 
actually required. 

By this method it is not necessary to deduct 
or add to the result obtained. The rise for each 
gram of good coal is somewhere about 6 deg. to 
7 deg. Fahr. for the 1934 grams of water, that 
being equivalent to about 11,500 to 13,500 units 
of heat. Graphite burns away quite easily in 



98 Practical Catechism. 

the oxygen apparatus. During the time the 
experiment is being made, Mr. Thomson finds 
it necessary to have the cylinder containing the 
water resting on three pieces of cork in a loose- 
ly-fitting vessel of bright tinned iron plate, hav- 
ing a slit 7 inches long and 1 inch wide cut 
down one side, through which the combustion 
can be observed. This vessel practically pre- 
vents loss of heat from the water if it is above 
the temperature of the surrounding air, vice 
versa if the temperature of the water be lower 
than that of the air, but Mr. Thomson prefers 
to have at hand a large supply of water which 
has been exposed to the atmosphere for some 
hours, in order that its temperature may be- 
come as nearly as possible the same as that of 
the air." 

GAS. 

Q. Does an ordinary gas-burner add very 
much carbonic acid to the air of a room ? 

A. A four foot burner produces (according 
to Hammond) more carbonic acid than the 
respiration of eight people. 

Q. Does a gas-burner add anything but car- 
bonic acid to the air ? 

A. Yes; the vapor of water; and some gas 



Practical Catechism. 99 

contains sulphur, which blackens silver, whether 
the gas be burned or only leaks out. 

Q. What is the secret in gas burning, to get 
the most light for a given number of cubic feet ? 

A. To burn it at a low pressure, and to have 
jet and tips which are best adapted to the press- 
ure and the kind of gas. This can be deter- 
mined only by actual experiment on each floor, 
or unless regulators are used on each floor, the 
higher levels will burn more gas, with the same 
sized tips, than those below. 

Q. How may a comparative photometer be 
made, for contrasting the illuminating power of 
different burners. 

A. Move some object like a lead pencil, along 
parallel to a line connecting the two burners — 
preferably in line with them — until the shad- 
ows made by the two flames, are equalized or 
neutralized. Then remembering, that the in- 
tensity of illumination at the testing point is 
inversely as the square of the distances, measure 
the distances from the pencil to each jet — if the 
equalizing is at (say) sixteen feet from one jet 
and nine from the other, the intensities of the 
burners will be as 4 to 3. If you turn down the 
more brilliant one until it equalizes the other at 
twelve and a half feet from each, the two jets 
will then be giving the same amount of light. 



100 



Practical Catechism. 



Q. Is there any way, other than by reading 
the meter, by which the amount of gas used in 
a private house may be determined ? 

A. It may be approximated, month by month, 
or week by week, by first finding out how many 
cubic feet of gas the tips burn per hour, each ; 
(generally five in private houses for usual press- 
ure and ordinary tips), then figuring up that so 
many parlor lights burn so many hours, so many 
in the hall, so long, so many in each bedroom, 
so many hours each ; and then taking their sum. 
Thus :— 



Parlor 

Hall 

Dining Koom 
Kitchen . . . 
1 Bedroom. 
1 " . 

1 " . 

Nursery . . . 



P.M. 



8. to 10.30 
6. " 11. 

6. " 8. 
5.30 " 9. 

7. " 8. 
8. 

10. 
6. 

7. 



" 11. 

" 7. 
" 7. 



6 jets at 2 J hrs. 
it it 5 a 

u a o u 



l 
l 
1 
l 
12 



hrs. 



15 
10 

6 
7 
1 
2 
2 
1 
3 



Total 47 

47X5=235 cubic feet per day; 235x30=7050 
feet per month. 

GEAR WHEELS. 

Q. What is the relative strength of gear teeth 
of different materials ? 



Practical Catechism. 101 

A. An English rule for pitch, to give equal 
strength, is: " Cast iron 1, brass 1.12, hard wood 
1.26, malleable iron 0.85, phosphor bronze 0.80, 
wrought iron 0.75, cast steel castings, say 0.70, 
cast steel forgings 0.50." Probably American 
cast iron need be of less relative pitch. 

Q. "We are putting in some core wheels, 
meshing with cast iron. Should they have the 
same thickness, or different ? " 

A. The pitch, of course, being the same, the 
wooden teeth should be one-fourth thicker than 
the cast iron. 

Q. What should be the percentage of loss by 
friction in gear wheels ? 

A. Very various, according to conditions. In 
a communication to an exchange, the loss of 
power by transmission through one pair of bevel 
wheels, when run dry, was 26 to 28 per cent. ; 
and when well oiled, S\ to 6J per cent. ; and the 
writer complains, with reason, that most gear 
makers have the idea that gear teeth roll togeth- 
er and work just as easy when dry as when well 
lubricated. There is a good deal in the design, 
construction, and operation of the gears, to make 
the friction vary between these limits. 

Q. " Please figure out the size of gear to trans- 
mit 40 horse power, from the following rule 
given by Cromwell's treatise on tooth gearing : — 



102 



Practical Catechism. 



Multiply the square root of all the force to be 
transmitted by .035. I don't exactly understand 
the formula." 

A. The formula to which we suppose you 
refer is on page 94 ; the rule being " to deter- 
mine the pitch of cast iron gears when the face 
width is equal to twice the pitch, multiply the 
square root of the total force to be transmitted 
by 0.055 for violent shock, 0.05 for moderate 
shock, or 0.35 for little or no shock." It will be 
observed that this rule is only for those gears 
where the face width is equal to twice the pitch ; 
and only for cases where there is little or no 
shock to be transmitted. 40 horse power may 
be carried by gears of a very widely differing 
diameter and running at very widely differing 
rotation speeds. 40 horse power is 40x33,000 
=1,320,000 foot lbs. per minute ; and this may 
be given by a force of 132 lbs. traveling 10,000 
feet a minute, or 1320 lbs. traveling 1000 feet 
per minute, or by any number of other combi- 
nations that will cipher up to 1,320,000 minute- 
foot-lbs. The number of feet per minute that 
the gear runs is not mentioned. We will sup- 
pose that it is to be on a shaft turning about 100 
times per minute ; and that the gear is to have 
about 10 feet circumference ; then there will be 
needed 1320 lbs. pressure with this speed of 



Practical Catechism. 103 

1000 feet per minute. Then to transmit a force 
of 1320 lbs. by a wheel having the face width of 
twice the pitch there would be required a pitch 
of .035 Vl320=.035X 36.33=1.27 inches; and 
the face of the gear would have to be 1.27x2= 
2.54 inches. If the gear was to be only 5 feet 
circumference and the number of turns per 
minute the same, the tooth would have to be 
.035 V / 2640=.035x51.38=practically 1.8 inches 
pitch ; and if the circumference were 10 feet and 
the number of turns only 50, the pitch would 
have to be, also, .035 V2fr40=1.8. 

Q. "I have an engine running 200 turns a 
minute and driving by gearing a geared cotton 
press, the main shaft of which turns 80 per min- 
ute. At present the pinion on the engine main 
shaft is 24 inches in pitch diameter. The cen- 
ters of these two wheels make an angle of about 
45 deg. with the horizontal. It is desired to 
lower the engine as much as possible, even if it 
involves some change in the diameter of the 
wheels and in the speed of the engine itself. 
The press speed cannot be changed. What 
would you recommend ? " 

A. Dropping the pinion until its center is 
directly under that of the large spur would low- 
er its shaft center nine inches, if the pitch 
radius of the large wheel is thirty inches. At 



104 Practical Catechism. 

present the speed ratio is as 200 to 80, and the 
pitch diameters as 24 to 60. To make the engine 
turn 320 to the press's 80 would call for only a 
fifteen-inch pinion upon the engine shaft if the 
diameter of the large gear was not changed. 
This would require raising the engine shaft four 
and a half inches above where it would be under 
the old speed, but with the pinion directly un- 
der the large spur. This would not do. 

To give the engine 320 turns to the press's 80 
and keep the pinion twenty-four inches, would 
call for a ninety-six-inch spur upon the press 
shaft, and leaving the press at its present height 
would drop the engine eighteen inches below 
where it would be with the speeds 200 to 80 and 
the pinion directly under the large spur. 

Slowing up the engine so as to make only 120 
turns and keeping the gear on the press the same, 
would call for a forty inch gear upon the engine 
shaft and put the engine shaft center fifty inches 
below the press shaft center. This would be 
only eight inches lower than having diameters 
60 and 24 and the gear centers in a vertical line. 

With engine speed 120 and press speed 80, 
and keeping the pinion 24 inches, the press gear 
need be only 36 inches, which would bring the 
gear centers only 30 inches apart and be worse 
than before. 



Practical Catechism. 105 

Increasing the pitch diameters of both gears 
in the same proportion, and keeping the speeds 
at 200 and 80, you can get any desired distance 
between the gear centers. Thus making the 
gears 90 and 36 instead of 60 and 24, the dis- 
tance between centers would be 63 inches instead 
of 42 ; making them 100 and 60 they would be 
80 inches apart, and so on. 

The same result may be attained by having 
an intermediate gear; thus, another 24 inch 
pinion may be inserted which would of course 
drop the engine 24 inches, and so on. But the 
more gears the more friction certain from the 
gearing proper, and the more there is likely to 
be from indirect friction by reason of the shafts 
not keeping in line, etc. 

GRAVITY.* 

Q. How can the earth be weighed ? 

A. One way is to place a pair of scales in 
the top of a tower and attach to each plate a 
wire which passes through a long tube to a 
point about sixty to one hundred feet below. 
To the lower ends fasten other scale plates, 
within say three feet of the ground. Under one 



* See also under Weights. 



106 Practical Catechism. 

of these lower plates, put a ball of lead about 
three feet in diameter. To prove that a body 
weighs more when near the earth than when 
further away, it is weighed in one of the upper 
scale pans with the weight in the opposite lower 
one; and then the weight and the body are 
changed in place and weighed against each 
other again. Then the weights are noted with 
the ball of lead under one of them and taken 
away. This shows the influence of the ball of 
lead at a given distance : from this there can be 
determined the attraction of the earth alone ; 
and taking diameters and distances, it may be 
ciphered out what the earth weighs, in tons, 
also what its average specific gravity is. Jolly, 
who invented this method, figures the mean 
density as 5.692 with a probable density of 
0.068, which agrees well enough with other 
determinations, especially that of Bailey, 5.67. 

Q. How can we calculate the lifting capacity 
of a balloon ? 

A. Multiply the capacity of the balloon in 
cubic feet by the difference in weight, in frac- 
tions of a pound, between a cubic foot of air and 
a cubic foot of the gas with which it is inflated ; 
subtract from the product the weight of the 
balloon and attachments. Figure a cubic foot 
of air at 34 deg. as 527.04 grains, or 0.07529143 



Practical Catechism. 107 

lb. avoirdupois ; hydrogen at 0.0052704 lb.; coal 
gas between 0.030116 and 0.05646 lb. 

Q. When the time of fall is given, how is 
the velocity acquired by a falling body calcu- 
lated? 

A. Multiply the time in seconds by 32.2 to 
get final velocity in feet per second. Thus in 5 
seconds the velocity acquired will be 5x32.2= 
161.0 feet per second. 

Q. When the time of fall is given how is the 
height found ? 

A. Multiply the square of the time in seconds 
by 16.1 to get the height in feet. Thus in 7 
seconds the fall will be 7x7x16.1=788.9 feet. 

Q. When the velocity is given how is the 
time of falling found ? 

A. Divide the velocity in feet per second by 
32.2 to get the time in seconds. Thus if the 
velocity reaches 100 feet a second, the time in 
falling was 100-f-32.2=3.105 seconds. 

Q. When the velocity is given how is the 
height of fall given ? 

A. Square the velocity in feet per second and 
divide by 64.4 to get the height of fall in feet. 
Thus a velocity of 150 feet a second is gained 
by a fall of 150x150-^64.4=34.9 feet. 

Q. When the height of fall is given how 
is the time of falling found ? 



108 Practical Catechism. 

A. Divide the height in feet by 16.1 and find 
the square root of the quotient, or the time in 
seconds. Thus when the height is 200 feet the 
time in falling will be V200-*-16.1== Vl.3646 
=1.17 nearly. 

Q. When the height of a fall is given how is 
the velocity calculated ? 

A. Multiply the height in feet by 64.4 and 
find the square root of the product, for the 
velocity in feet per second. Thus where the 
height is 90 feet the velocity will be V90X64.4 
= 1/5796=76. 

Or multiply the square root of the height in 
feet by 8.025 to get the velocity in feet per 
second. Thus for the last case V90X 8.025= 
9.4868X8.025=76.1316. 

Q. A body takes six seconds to fall from a 
height ; with what velocity does it strike ? 

A. 32.2X6=193.2 feet per second. 

Q. What was the height of the fall ? 

A. 16.1X6X6=579.6 feet. 

Q. A ball strikes with a velocity of 500 feet 
per second. How long was it in falling ? 

A. 500-^32.2=15.53 seconds. 

Q. From what height did it fall ? 

A. 500x500-64.4=3880 feet. 

Q. How long would it take a stone to fall 
208 feet? 



Practical Catechism. 109 



A. V208-s-16.1= V12.92 = 3.6 seconds. Or 
V208h-4=14.4h-4=3.6 seconds. 

Q. A body falls 400 feet ; what is the striking 
velocity ? 

A. V400X 64.4=160.5 feet per second. Or 
20X8.025=160.5 feet per second. 

Q. A ball weighing five pounds is struck 
with such force as to give it an initial velocity 
of 60 feet per second on a level field, and the 
frictional resistance to its movement is one 
pound. How far will it go before it comes to a 
rest? 

-^ — „, , —279.5 feet. Or, as the retard- 
1X64.4 ' 

ation is one-fifth the weight, (60 2 X 5)-s-64.4= 

279.5 feet. 

HARDENING AND TEMPERING.* 

Q. Does heating to redness and quenching 
harden all steels ? 

A. No ; some mild steels for boiler and bridge 
work are softened by such treatment. 

Q. Which are most liable to crack and warp 
or twist in hardening, hard steels or soft ? 

A. Hard. 



*See also under Iron and Steel. 



110 Practical Catechism. 

Q. Which expands the most in heating, hard 
steel or soft ? 

A. Hard. 

Q. What is the effect of hardening upon the 
volume and density ? 

A. Hardening increases the volume and de- 
creases the density. 

Q. W T hat is the effect of long heating to a 
high temperature upon steel ? 

A. It is apt to drive out the carbon and make 
the grain coarse. 

Q. What is the best flux for welding steel ? 

A. Melted and ground borax. 

Q. How should annealing steel be done ? 

A. By cooling slowly in contact with large 
mass of heated iron which is cooled at the same 
time. 

Q. How can loss of carbon, or deoxidizing, be 
prevented, in heating for temper ? 

A. It may be done in melted lead for large 
articles, or in melted glass for small articles 
like watch springs. 

Q. How may springs be uniformly heated for 
tempering, without deranging their shape ? 

A. They should be coiled around a mandrel, 
or what is better, a fire may be made about a 
piece of gas pipe in which the spring is in- 
serted. 



Practical Catechism. Ill 

Q. What is the most reliable method of tem- 
pering an ordinary spring ? 

A. To blaze it off by boiling it in oil, setting 
the oil on fire and re-dipping, aud so on several 
times. 

Q. What is a good oil composition for spring 
hardening ? 

A. Spermaceti oil . . , 48 

Neats-foot oil 47 

Rendered beef suet 4 

Resin 1 

100 

Q. What special treatment should chrome 
steel have in tempering ? 

A. All chrome steel tools which are drawn 
from a large body to an edge should be allowed 
to cool off after forging, and should be re-heated 
for tempering, as the interior of the mass re- 
tains the heat of forging after the surface has 
cooled. 

Q. How can the maximum strength and 
hardness be got out of chrome steel ? 

A. By hardening it at the lowest heat pos- 
sisible — dark cherry red, seen only in the 
shade. 

Q. Why is water such an efficient hardening 
fluid? 



112 Practical Catechism. 

A. Because it has a high specific heat and 
great capacity for taking up heat while vapor- 
izing. 

Q. How may water be made to act with the 
greatest efficiency in hardening steel ? 

A. By being thrown upon the metal in fine 
spray. 

Q. May steels be hardened in any other way 
than by heating and quenching ? 

A. Yes; by compression under the hammer 
or by a hydraulic press, the latter being the 
better of the two. Metals may be compressed 
to increase their density and held compressed 
while they cool from full cherry red. 

Q. What is the chemical effect of this com- 
pression ? 

A. To lessen the proportion of free carbon 
and increase that of the combined carbon. 

Q. " If I heat steel and then quench it, will 
it change its length ? If so, will it get longer 
or shorter ? " 

A. Some few steels do not change their 
length ; most of them shorten by heating and 
then quenching. 

Q. " What is the best bath for hardening a 
mill pick?" 

A. To say which is the best, out of the great 



Practical Catechism. 113 

number which are so strongly recommended, 
would be a difficult undertaking. The follow- 
ing is said to be very successfully used : — 2 
gallons of rain-water, 1 ounce corrosive subli- 
mate, 1 ounce sal ammoniac, 1 ounce saltpetre, 
H pints rock salt. The pick is heated to a 
cherry red and cooled in the bath. It is found 
that the effect of the salt is to harden the steel, 
while it derives toughness from the other ingre- 
dients. The pick is left without drawing the 
temper, and is then not liable to break. 

Q. Are there any irons which will harden by 
heating to redness and then quenching in cold 
water ? 

A. Yes ; but very few. 

Q. What is the effect of tempering on an- 
nealed bronze ? 

A. Just the reverse of its effect on annealed 
steel ; it makes it soft. 

heating.* 

Q. Is there any rule for finding the length of 
pipe required for heating the air in a building 
by steam, of say 5 lbs. pressure by the gauge ? 



* See also under Combustion and Fuels. 



114 Practical Catechism. 

A. Multiply the volume of air in cubic feet 
to be warmed per minute, by the difference of the 
external and internal temperatures, and divide 
the product by 84 for one inch pipes, by 168 for 
two inch, by 252 for three inch, and by 336 for 
four inch pipes. The quotient will be the length 
of pipe in feet. The number of cubic feet to be 
warmed per minute will be determined very 
largely by the ventilation, which should take 
out, in winter, 3 J to 5 cubic feet per minute per 
person in the room. 

Thus for a room 30x20x12, with ten persons 
in it, there would be required to heat 50 cubic 
feet per minute, to 70 deg. Fahr., when the 
outer air was 25 deg., 50x45-*-84=2250-r-84= 
nearly 27 feet of one inch pipe, supposing no 
radiation from the wall. 

Q. Has any rule been arrived at, or table 
made, which will show the quantity of coal re- 
quired to be consumed per hour in an ordinary 
boiler to heat a given length of pipe ? 

A. Of course such a table could only be ap- 
proximate ; but this one of Hood's will probably 
serve very well as a guide : — 



Practical Catechism. 



115 



COAL CONSUMED PER HOUR TO HEAT 100 FEET 
OF PIPE, FOR GIVEN TEMPERATURE DIF- 
FERENCE OF THE PIPE AND AIR. 



Diam. 


Difference of Temperature of the Pipe and the 


of 


Air in the Room in Fahrenheit Degrees. 


Pipe. 


150 
lbs. 


145 
lbs. 


140 
lbs. 


135 
lbs. 


130 
lbs. 


125 
lbs. 


120 


Inches. 


lbs. 


4 


4.7 


4.5 


4.4 


4.2 


4.1 


3.9 


3.7 


3 


3.5 


3.4 


3.3 


3.1 


3. 


2.9 


2.8 


2 


2.3 


2.2 


2.2 


2.1 


2. 


1.9 


1.8 


1 


1.1 


1.1 


1.1 


1. 


1. 


.9 


.9 



Diam. 


Difference of Temperature of the Pipe and the 


of 


Air in the Room in Fahrenheit Degrees. Cont. 


Pipe. 


115 
lbs. 

3.6 


110 
lbs. 

3.4 


105 
lbs. 

3.2 


100 
lbs. 

3.1 


95 
lbs. 

2.9 


90 
lbs. 

2.8 


85 
lbs. 

2.6 


80 


Inches. 


lbs. 


4 


2.5 


3 


2.7 


2.5 


2.4 


2.3 


2.2 


2.1 


2. 


1.8 


2 


1.8 


1.7 


1.6 


1.5 


1.4 


1.4 


1.3 


1.2 


1 


.9 


.8 


.8 


.7 


.7 


.7 


.6 


.6 



The question often arises, how much pipe is 
required to heat a building of a certain cubic 
capacity ? Of course this varies with the tem- 
perature of the steam used, the degree of heat 
required to be kept up, the frequency with 
which the doors are opened, the temperature of 
the outside air, the intensity of the wind, the 
area of window surface, etc., etc. There are no 



116 Practical Catechism. 

two places in which the conditions are exactly 
alike, and it would be hard to lay down an abso- 
lute rule for any fixed set of conditions. But 
there are some good data which will do to start 
from. 

We may start out with the fact that one unit 
of heat will raise 55J cubic feet of air from 62 
deg. to 63 deg. Fahr., and can use these figures 
no matter what the temperature and the steam 
are of the building to be warmed, or what out- 
side atmosphere. 

For low pressure steam — say about 5 lbs. above 
atmosphere, or by the gauge — the length of 4 
inch pipe required for heating the air is found 
by multiplying the volume of air in cubic feet 
per minute, to be warmed, by the difference of 
the temperature in the room and outside, and 
dividing by 336. The answer will be the length 
of 4 inch pipe in feet, and will be also about 
the number of square feet of pipe, as a 4 inch 
pipe has 12.57 inches circumference, hence but 
a very trifle over 144 square inches of surface 
per foot of length. (For one inch pipes the 
divisor required is 84 instead of 336.) 

It will take about one square foot of direct 
boiler surface or its equivalent of floor surface 
to keep a temperature of 60 deg. Fahr. in a 
room with steam at 5 lbs. by the gauge, and the 



Practical Catechism. 117 

ordinary range of temperature in and out of the 
room. 

Q. What amount of 2| inch, also of 1 inch, 
pipe would it require for a room of 9,000 cubic 
feet ; the boiler pressure being 1 lb.? 

A. To find the amount of 2f" and also of 1" 
pipe to heat a room of 9,000 cubic feet, the 
boiler pressure being 1 lb. by the gauge, or say 
2.16 deg. Fahr. in temperature, and the room to 
be kept at 65 deg. Fahr. and have its air 
changed every half hour (outside temperature 
being 40 deg. Fahr.) : Multiply the volume of 
air to be warmed, in cubic feet per minute, 
(300) by the difference between the required 
temperature of the room, and the external 
temperature (25 deg.) and by J, and divide by 
the difference between the internal temperature 
and that of the pipes (150 deg.), this gives the 
number of feet of four inch pipes, as 24.80. 
Of one inch pipe it would take 24.80x4=92.20 

lineal feet ; and of 2 J inch pipe, ^j-of 24.80= 
36.07 lineal feet. 

Q. "How much steam at atmospheric pres- 
sure will it take to melt one cubic foot of 
snow ? " 

A. That depends upon whether the steam is 
dry or wet, and whether the snow is wet or dry, 



118 Practical Catechism. 

loose or packed; also upon its temperature. 
When the thermometer is at 10 deg. below zero, 
snow lying upon the ground is colder than 
when the temperature of the air is only 30 deg. 
Fahr. But supposing the snow to be dry, to 
take up ten times as much bulk as an equal 
weight of water, and have a temperature of 32 
deg. Fahr., you would need about 21 or 22 
cubic feet of dry steam at 212 deg. Fahr., as a 
minimum. 

Q. " What amount of freshly-fallen snow, in 
cubic feet, at a temperature, respectively, of 32 
deg., 20 and 10 deg., will 1 cubic foot of steam 
at 212 deg., melt?" 

A. On the assumption that 10 cubic inches of 
snow are equivalent to 1 cubic inch of water, 
which is the equivalent accepted by the United 
States Signal Service, 1 cubic foot of steam, at 
212 deg. Fahr., will melt 
0.0473 of a cubic foot of snow at 32 deg. Fahr. 
0.0454 " " 20 " u 

0.0439 " " 10 " " 

Or, to state the case inversely, to melt 1 cubic 
foot of snow at 
32 deg. Fahr., will require 21.14 cubic feet of 

steam at 212 deg. Fahr. 
20 deg. Fahr., will require 22.03 cubic feet of 
steam at 212 deg. Fahr. 



Practical Catechism. 119 

10 deg. Fahr., will require 22.78 cubic feet of 
steam at 212 deg. Fahr. 

Q. How hot will air get when it is com- 
pressed ? 

A. That depends upon the amount of pressure 
before and after the compression. If one 
pound of air is compressed into three cubic feet 
and has a pressure of 150 lbs. per square inch 
by the gauge, it will have a temperature of 
3x164.7x2.-7.74=676.53 deg. Fahr. 

If the pound of air occupies six cubic feet and 
had the same pressure of 164.7 lbs. absolute, the 
temperature would be 2,214.2 deg. Fahr. 

Q. What is the relative capacity for heat of 
water and quicksilver ? 

A. The quantity of heat which would raise 
one pound of water from 60 deg. to 61 deg. 
Fahr., would give an equal increase of temper- 
ature to 30 lbs. of quicksilver (mercury). 

HYDRAULICS. 

Q. Which is more effective, a hydraulic jack 
or a screw ? 

A. The hydraulic, by two or three to one, as 
proved by actual test; there is so much less 
friction. One man with one hand has been 
known to do more work with a hydraulic jack 
than three men working with a screw jack. It 



120 Practical Catechism. 

took 960 men and 75 horses with 40 capstans to 
raise the obelisk at Rome; 480 men with ten 
capstans to raise that at Paris ; four men with 
four hydraulic jacks to raise Cleopatra's needle. 

Q. Would it make any difference in the lift- 
ing force of a hydraulic ram if the piston have a 
curved instead of a flat surface next the work ? 

A. No. It is the net cross section of the 
cylinder or the net flat area of cross section of 
the piston that determines its force. 

Q. What is the essential or cardinal principle 
in designing turbine wheels ? 

A. That the water shall strike the wheels 
without shock and leave it without velocity. 

Q. How can the number of cubic feet of water 
that will flow through a hole in the side of a 
box be determined ? 

A. Multiply the area of the orifice in square 
feet by the number of seconds, and the product 
by 5.05 times the square root of the height of 
the head of water (in feet) above the orifice. 

Q. What are the two most simple rules for 
estimating the quantity and velocity of water 
(in a stream or creek) in passing a certain 
point ? 

A. The two most frequently employed are by 
the weir and by the current meter. The latter 
is the most simple. It consists of a little pro- 



Practical Catechism. 121 

peller wheel, the number of revolutions of 
which are registered by clock work. The cross 
section of the stream at the point where the 
current meter is immersed is carefully measured 
where possible ; and where not possible to 
measure it, it is estimated. The meter is al- 
lowed to register for a certain length of time 
and the number of revolutions noted. A table 
generally comes with each instrument, so that 
the flow in gallons per minute per square foot 
of cross section can be approximated. The ob- 
jection to this very simple method is that cross 
sections of the same area but different shape 
give different quantities of flow ; for instance a 
wide, flat cross section would have more retard- 
ation due to friction of the bottom than one hav- 
ing a minimum amount of side and bottom 
surface for the same cross area. As a general 
thing it will be found that the current meter 
will register various amounts at different posi- 
tions and different distances from the shore. 

The other method is by a weir or dam of 
boards thrown across the entire stream so as to 
confine its flow to a space cut out of the crest of 
the dam, and having a given length and height. 
The depth of water flowing in the cut in the 
top of the weir is carefully taken ; the width of 
the effective part of the weir is taken, and then 



122 Practical Catechism. 

there are employed figures and coefficients and 
tables of which no two agree, because no two 
are made up from the same character of condi- 
tions ; so that I very much question if the re- 
sults are within fifty per cent of the truth. 

The reasons for the weir measurement being 
so unreliable are that it really requires that the 
heads on, at and above the weir should be taken 
in order to determine the true discharge ; the 
crests are not the same width in different tests, 
and this varies the rate ; the nature of the ap- 
proach also affects the rate of the flow. When 
the weir extends from side to side of the chan- 
nel, the contraction is less than when it forms a 
notch ; and when it runs only about one-fourth 
of the whole stream width the reduction to be 
made is sometimes more than forty per cent. 
Where the overflow is a thin plate it discharges 
a greater proportionate quantity when the 
stream is only one inch deep than with greater 
depths; and when wing boards are added, the 
deduction for contraction is less than where 
there are none. When the heads remain the 
same, the coefficients decrease, at first more, and 
then less rapidly than the breadths of the weirs. 

These things being the case, it seems difficult, 
if not impossible, to give any rule that will be 
applicable to any particular case unless all the 



Practical Catechism. 123 

details of the case are stated with a degree of 
completeness and accuracy hardly likely to be 
obtained in every day practice. 

IRON AND STEEL.* 

Q. " What proportion between the tensile 
strength of wrought iron with and that against 
the grain or fibre ? " 

A. Tensile strength of wrought iron averages 
10 per cent, more with the fibre than across it. 

Q. Should wrought iron have any fibre at 
all? 

A. No ; it would not have if there were not 
imperfections in its manufacture, by which the 
slag cells are squeezed out into tubes, instead of 
the slag being entirely removed. 

Q. " I heard a statement made that the ten- 
sile strength of ordinary cast iron was only 
about twice as much as that of w r hite pine ? Is 
that so?" 

A. We may put ordinary cast iron at about 
20,000 lbs. per square inch, tensile ; white pine 
at about 10,000 lbs. 

Q. How may iron castings be stuffed ? 



*See also under Coloring Mechanical Objects, Found- 
dry Practice, Hardening, Tempering and Annealing, 
and Strength of Materials. 



124 Practical Catechism. 

A. By a heavy coat of paint, which is then 
rubbed down with pumice stone, and next cov- 
ered with the proper thin coat of paint. 

Q. What is the effect of cold rolling on iron ? 

A. Cold rolling increases its strength. 

Q. What memorandum should be made con- 
cerning cold rolled shafting ? 

A. It will curl if splined. 

Q. " Is the ' skin ' of wrought iron the strong- 
est portion ? " 

A. No. 

Q. Is crystallization of iron caused by long 
continued vibration ? 

A. There are many who consider that long 
continued vibration will change fibrous iron to 
crystals ; while others as stoutly maintain that 
those specimens of iron which after long use are 
broken and show crystalline fracture were never 
good iron at all. It is difficult to prove either 
side of the case; although one experimenter 
says that having hung up a bar of iron and had 
it hammered upon the end by automatic mach- 
inery for a long period of time, it broke off in 
the center, showing a crystalline fracture at the 
break. 

Q. Of two irons both of high strength and 
ductility, which will draw into the finest wire ? 

A. The one which is lowest in both qualities. 



Practical Catechism. 125 

Q. What kind of iron is best for wire draw- 
ing? 

A. Charcoal bloom, if free from cinder and 
coal. 

Q. What are the tests or signs of a good 
rivet ? 

A. A good rivet, cold, should bend double 
without breaking. The head should flatten out, 
when hammered hot, to J inch thick without 
fraying at the edge, or breaking. 

Q. What is the principal cause of differences 
in the strength and the welding power of 
wrought iron ? 

A. The amount of its reduction in rolling. 

Q, Is the strongest iron necessarily the best 
for chains, etc. ? 

A. No ; tests show that for two-inch bar iron 
for chain cable, the strength should be between 
48,000 and 52,000 lbs. per square inch, and for 
one inch, between 53,000 and 57,000 ; and that 
stronger irons than these are not good for cables 
because they have low ductility and poor weld- 
ing quality. 

Q. What is much desired in welding ? 

A. A non-oxidizing atmosphere. 

A. What is the effect of adding carbon to 
iron ? 

A. It hardens it, lessens its ductility and 



126 Practical Catechism. 

malleability, and renders it more fusible and 
less elastic. 

Q. In what proportions must the carbon be 
in order to make a steel that will harden and 
take a temper ? 

A. Between one-half and two per cent. 

Q. How is case-hardening done ? 

A. It is practically the cementation process 
carried out so as to steelify only a thin outside 
layer. » 

Q. What is the mixture used in case-harden- 
ing? 

A. 90 per cent, carbon and 10 of carbonate of 
lime or of carbonate of potash is a usual mix- 
ture. Sometimes a prussiate of potash (potas- 
sium ferrocyanide) is added. 

Q. Which is better in working shear steel — 
the hammer or the rolls ? 

A. Tilted steel is better than rolled. 

Q. What is the action of manganese in mak- 
ing crucible steel ? 

A. From one-eighth to one per cent of it en- 
ables the use of poorer metal. It corrects red 
shortness, and is an antidote to sulphur. It 
produces hardness without brittleness and gives 
the steel greater malleability at high heats. It 
also reduces liability to formation of blow holes 
in the ingot. 



Practical Catechism. 127 

Q. At what temperature is crucible steel 
made? 

A. Probably 3,600 deg. Fahr. 

Q. Why is it necessary to exclude air from 
the melting pot in crucible steel making ? 

A. Because melted steel absorbs oxygen read- 
ily ; and more so at high temperature and with 
low proportion of carbon. 

Q. What is the direct process of steel mak- 
ing? 

A. Practically the same as for making malle- 
able iron (not malleable castings) except that if 
the carbon is all taken out, spiegeleisen is added 
to bring up the proportion of carbon to the 
proper point. 

Q. Is there any material which will take sul- 
phur out of melted steel ? 

A. There is none which will remove it. 
Manganese will counteract it, but it will be left 
in the steel and will show by analysis. 

Q. What is the effect of tungsten upon steel ? 

A. To harden it without lessening its tough- 
ness. 

Q. What is the theory of making Bessemer 
steel ? 

A. Forcing air through melted cast iron so 
as to burn out the carbon and the silica. 

Q. Which is burned out first ? 



128 Practical Catechism. 

A. The silica. 

Q. What is the next process to burning out 
the silica and the carbon ? 

A. Adding spiegeleisen, the carbon of which 
brings up the carbon percentage of the iron, 
while its manganese withdraws the oxygen from 
the melted metal. 

Q. If the metal was run off without being re- 
carbonized, what would it be ? 

A. Practically a malleable iron or wrought 
iron. 

Q. How is Mushet's steel made ? 

A. Pulverized wolfram is mixed with its own 
weight of melted pitch ; this mixture is added 
to the iron and the flux in the crucible, and the 
whole melted in the steel furnace at a high 
heat. 

Q. What are the peculiarities of tungsten 
steel? 

A. The harder grades cannot be cut with the 
file, and no tungsten steel can be tempered ; it 
must be worked into shape at one operation and 
ground to exact form. It makes very perma- 
nent magnets. 

Q. What is the effect of phosphorus on steel ? 

A. It makes it hard, and less ductile, and 
makes it " cold - short," that is, brittle when 
cold. 



Practical Catechism. 129 

Q. What does sulphur do to steel ? 

A. Makes it brittle at high temperatures. 

Q. What is the antidote to sulphur in steel ? 

A. Manganese. 

Q. What is the effect of silicon on steel ? 

A. Hardens it and makes it weld better. 

Q. What is the effect of copper upon steel ? 

A. Thurston finds it hardening. 

Q. What is the purest known commercial 
iron ? 

A. The best sample on record (Lowmoor bar) 
contains 99.798 of iron and 0.272 of carbon ; 
there being only a trace of sulphur, and abso 
lutely no silicon, phosphorus, or manganese. 

Q. How may the different grades of steel be 
distinguished and named ? 

A. In lieu of any really definite name for the 
different qualities of iron which are called 
"steel" in popular parlance, manufacturers 
have adopted a system of numbering that gives 
some notion of the condition of the product by 
designating the relative amount of carbon that 
the converted iron has received. 

Soft and low steels are known as from 0.10 to 
0.76 of carbon ; the lower grades are merely 
purified iron, with none of the qualities of cru- 
cible steel, they weld without flux, work soft at 
high heats, are not burned when approach the 



130 Practical Catechism. 

welding heat, and are affected by sudden chill- 
ing in a cold bath only as iron would be. As 
the numbers approach a full per cent, of car- 
bon, the steel begins to act like crucible steel ; 
requires a flux for weld, chills and hardens in 
water, and is capable of being tempered and of 
receiving a cutting edge. This method of des- 
ignation is much better than the loose naming 
of the differing grades " iron " and " steel." 

A. Can cast steel be welded ? If so, how ? 

A. Mr. Benjamin Askew, of Glasgow, Scot- 
land, has discovered that cast steel may be 
readily welded by using plaster of Paris as a 
flux. 

A committee appointed by the Scottish Soci- 
ety of Arts, before whom his paper was read, 
also investigated the matter and fully confirmed 
Mr. Askew' s conclusions, but they drew atten- 
tion to the fact that the difficulty of welding- 
cast steel depends very much on the percentage 
of carbon it contains. They give the following 
rules on the subject, which may be compared 
with those laid down by the Seraing Works 
(John Cockerill & Co.) : 

Kazor steel, 1 J per cent, carbon ; easily burnt 
and requires skillful handling. 

Saw and file temper, f per cent, carbon ; 
should not be heated above a cherry red. 



Practical Catechism. 131 

Tool temper, 1J per cent, carbon ; can be 
welded, but not without care and skill. 

Spindle temper, 1 J per cent, carbon ; requires 
considerable care in welding. 

Chisel temper, 1 per cent, carbon; may be 
welded without much difficulty. 

Below this last^come the various forms of medi- 
um and mild steel, which are easily weldable. 

While the welding of steel may thus be said 
to be with difficulty overcome, the same cannot 
be said of another operation, very useful in or- 
dinary engineers' practice, namely, case-harden- 
ing. Experience shows that case-hardening is 
not possible except with the very mildest de- 
scriptions of steel, or rather iron containing not 
above 0.18 per cent, of carbon. An attempt to 
case-harden steel which is beyond this limit of 
carbon not only fails, but makes it rotten. It is 
very desirable that this difficulty, and also the 
failure of steel when welded at a black heat, 
should be thoroughly examined and if possible 
corrected ; otherwise there are certain purposes 
for which wrought iron is likely after all to hold 
its ground. 

Q. What makes iron hard or easy to weld ? 

A. Generally, the presence of some foreign 
body ; as silicon, sulphur, phosphorus, oxygen, 
etc. 



132 Practical Catechism. 

Q. How is " Chester steel " made ? 

A. The castings are first made in hard " gun 
metal " (gun iron) or Bessemer iron, in green- 
sand ; and then annealed. 

Q. "Is steel increased in strength by com- 
pressing it while in the mold ? " 

A. Compressing melted steel with a pressure 
of about six tons per square inch increases its 
strength. 

Q. What is the effect of re-rolling on iron 
bars? 

A. Reheating and rolling down or forging 
down wrought iron bars reduce their elongation 
and increase their tensile strength. 

Q. Can hard iron be cold-rolled ? 

A. But very little. 

Q. Can hard steel be cold-rolled ? 

A. No, not at all. 

Q. What are the effects of cold-rolling upon 
pure soft puddled iron ? 

A. To increase the tenacity from 25 to 40 per 
cent., and the resistance to transverse strains 
50 to 80 per cent ; raise the elastic limit under 
twisting, pulling and cross-breaking strains, 
from 80 to 125 per cent ; raise the elastic resil- 
ience from 300 to 400 per cent., and the elastic 
resilience in transverse strains from 150 to 425 



Practical Catechism. 133 

per cent. ; give a smooth bright surface free from 
scale of black oxide, enable the stock to be made 
exactly to gauge and if worked with tools wear 
them less than working down hot-rolled iron. 
Besides this the cold-rolled metal resists strains 
more uniformly, and is more uniform in density 
and in strength from inside to outside. The 
ductility is diminished as the density increases. 

Q. May rupture of material be caused by re- 
peated strains, none of which attain the abso- 
lute breaking limit ? 

A. Yes ; the differences of the limiting 
strains may be sufficient for the rupture of the 
material. The number of strains required for 
rupture increases much more rapidly than the 
weight of load diminishes. This has been 
proved by Wohler and by Spangenburg, who 
have showed that the permanence and safety of 
any iron or steel structure depends not simply 
upon the greatest magnitude of the load to be 
held, but on the frequency of its application and 
the range of variation of its amount. 

Q. What is the effect of forging on large 
masses of iron and steel ? 

A. Where there has been repeated piling and 
welding, hammering is apt to lessen and weaken 
the mass in the center ; while the heating over 
and over again spoils the external metal. 



134 Practical Catechism. 

Q. What is the effect of temperature upon 
the fracture of steel and iron ? 

A. Samples broken in one place at a temper- 
ature of 20 deg. Fahr., and in another at a tem- 
perature of 75 showed in the first case a granu- 
lar or steel and iron fracture, and in the other a 
fine clear fibrous grain — the two fractures being 
but four inches apart. 

Q. What effect has the speed of breaking 
upon the fracture ? 

A. A granular fracture may be produced by 
shock, in iron which appears fibrous when 
gradually torn apart. 

Q. How may tempered steels have their 
density and ductility adjusted to any desired re- 
lation (within a limited range) ? 

A. By rehardening and tempering. Thus if 
steels are too hard they may be heated and tem- 
pered in oil at a temperature lower than at that 
which they would previously temper. They 
will increase the extension without too greatly 
diminishing the breaking strain. If the break- 
ing strain is too low and the extension high, the 
new tempering is done at a higher temperature 
than the first one. 

Q. Does jarring always lessen the density of 
iron or steel ? 

A. No, it may improve it ; an instance being 



Practical Catechism. 135 

in iron rails laid on the Camden and Amboy 
K. R. in 1832, which were taken up after many 
years, much improved in quality. 

Q. Is there any improvement or deteriora- 
tion of iron by keeping when not in use ? 

A. Yes, it generally improves by age; the 
particles getting adjusted after the severe 
strains of drawing. 

Q. Does the speed of working have any effect 
upon the amount of work done to produce a 
given amount of change of form ? 

A. Yes; it takes more work in foot pounds 
to do a given amount of hammering, rolling, 
forging and welding in a short time, than in a 
long one. The longer time that can be taken 
(without re-heating) the less power is needed. 

LIMES, MORTARS AND CEMENTS.* 

Q. What is the difference between mortar, 
concrete and cement ? 

A. Mortar and concrete are made with lime ; 
the former containing from three to three and a 
half parts of sharp sand to one of lime, and the 
latter containing about four of gravel and two 
of sand to one of lime. Cement may be com- 



*See also under Building, Bricks, etc. 



136 Practical Catechism. 

posed of pure Portland cement alone, or it may 
have mixed with it from one to three parts of 
sand. 

Q. How are hydraulic limes made ? 

A. By calcining stone containing from 18 to 
20 per cent, of silicate of alumina, or of carbon- 
ate of alumina, or of both combined. 

Q. What are the peculiarities of hydraulic 
limes ? 

A. They slack more slowly than air lime, 
and the best harden very slowly under water or 
where it is very wet. 

Q. What are hydraulic cements ? 

A. They are made by calcining limestone 
" containing 30 to 60 per cent, of clay. They do 
not slack, and their pastes harden very rapidly 
under water. 

Q. What will delay the setting of plaster of 
Paris? 

A. Two per cent, of alum or borax will delay 
it three to four hours, but will make a hard and 
heavy mass. 

Q. How is English Portland cement made ? 

A. By grinding together chalk and clay. It 
is the strongest in the market. 

Q. How is Roman cement made ? 

A. From limestone containing clay and iron. 

Q. What is hydraulic mortar ? 



Practical Catechism. 137 

A. Mortar made with hydraulic lime and 
sand ; sometimes being tempered with clay or 
lime to retard its setting. The slower it sets the 
firmer and harder it gets. 

Q. What is hydraulic cement ? 

A. A mortar made with hydraulic lime or ce- 
ment, but no sand. It sets quickly if warm ; 
does not shrink much in setting. 

Q. How should hydraulic cement be mixed ? 

A. With about one-third its volume of water. 

Q. How should it be laid ? 

A. In very thin joints. 

Q. Which is the better for mortar; river 
sand or sea sand ? 

A. River sand, as it is less apt to be rounded ; 
and is free from salt. 

Q. What proportions may be given mortars 
for stone work ? 

A. 15 to 20 per cent, cement, 6 to 8 lime, and 
the rest sand. 

Q. W T hat proportions of mortar for brick ? 

A. 10 per cent, less sand than for bricks. 

Q. How is stucco made ? 

A. Two of sand to one of cement ; sometimes 
sugar or molasses is added. 

Q. How much does concrete swell in setting ? 

A. About 3 per cent. 



138 Practical Catechism. 

Q. What is the proportion between the 
gravel used in making concrete, and the con- 
crete itself after setting and ramming ? 

A. A cubic foot of gravel makes about four- 
fifths of a cubic foot of well rammed concrete. 

Q. Whatisbeton? 

A. Concrete in which hydraulic lime or ce- 
ment is used instead of fat lime. 

Q. What is beton-Coignet ? 

A. Lime, 4 parts ; hydraulic cement, 1 to 2 ; 
sand, 20 ; first mixed dry and then in a mill 
with a little water ; then molds filled with the 
mixture, which is well rammed in them. 

Q. What are its peculiarities ? 

A. The small volume of water used, its quick 
setting and great strength. 

Q. Does mortar increase or decrease with 
age? 

A. It increases. Sometimes it doubles or 
even trebles its original strength. Some old 
mortar is so strong as to allow the bricks which 
it joins to be broken before it will part. 

LOCOMOTIVES. 

Q. Does the tractive power of a locomotive 
vary with its speed ? 
A. P. H. Dudley's tests show that in starting 



Practical Catechism. 139 

a train the adhesion of steel-tired drivers upon 
a dry steel track is about one-third the weight 
upon them ; but as the speed increases this is 
reduced probably from eighteen to twenty per 
cent, at fifty miles per hour. 

Q. How can you find the size of rail required 
for a locomotive ? 

A. Multiply the number of net tons (of 2000 
lbs. each) on one driving wheel by ten, and that 
will give the pounds per yard of the lightest 
iron rail practicable. Where there is more 
weight upon one pair of wheels than upon 
others, the heaviest should be taken. 

Q. What is a consolidation locomotive ? 

A. An eight-coupled ten-wheeler; that is 
there are eight driving wheels and two leading 
wheels. 

LUBRICATION. 

Q. W T hich is the better, intermittent lubrica- 
tion or continuous ? 

A. That which is continuous and regular. 
Thus Webber found for continuous oiling a 
coefficient of friction of .044 as against .066 for 
intermittent. Morin obtained .042 as against 
.075 ; Clark .043 as against .070. 

Q. What should be the characteristics of a 
good lubricant? 



140 Practical. Catechism. 

A. It should have enough body to keep the 
surfaces between which it is introduced, apart ; 
a low coefficient of friction in actual use ; high 
capacity for carrying away heat, freedom from 
tendency to decompose or to gum, either before 
used or during use; absence of acid of other 
substances which would act upon the bearing 
surfaces ; high temperatures of vaporization 
and decomposition ; low temperature of thicken- 
ing ; freedom from grit or other foreign sub- 
stances; and last, special adaptability to the 
work to be done ; thus a lubricant may be very 
good for light bearings but very poor for heavy 
ones and vice versa. 

Q. What should be the characteristics of a 
good mineral lubricating oil ? 

A. It should flash above 300 deg. Fahr. (150 
deg. C); should not lose more than 5 per cent, 
of weight in ten hours at a temperature of 60 
deg. Fahr. ; should be fluid enough to remain in 
place; should have great adhesion to metallic 
surfaces and little cohesion in its own particles, 
and freedom from acid and from grit. 

Q. What is the best animal oil to give body 
to mineral oils, for lubricating ? 

A. Sperm. 

Q. What will make a good railroad grease ? 

A. Equal parts of tallow and palm oil, with 



Practical Catechism. 141 

water to which there has been added one-eighth 
of its weight of caustic soda; they should be 
mixed warm. 

Q. What is a good lubricating grease for 
heavy slow-moving journals ? 

A. Two parts paraffine, one of lard and three 
of lime-water ; or eight parts of bayberry wax to 
one of graphite. 

Q. How should soapstone be prepared for use 
as a lubricant ? 

A. It should be ground fine, sifted, washed to 
remove grit, steeped in muriatic acid to remove 
iron, washed to remove the acid, then dried, 
ground and sifted again. It is best used with 
about one-third its weight of paraffine, rape or 
other lubricating oil ; or with a lubricating soap. 

Q. What are the pressures which may be 
permitted upon various journals and bearings ? 

A. 800 lbs. to the square inch is high for 
wrought iron even at slow speeds ; 1200 lbs. 
may be given steel crank pins of marine en- 
gines; 7000 to 9000 has been put on slow- 
moving and seldom-moved pivots of swing 
bridges. Higher pressures than 600 to 1000 
lbs. on iron and steel should be avoided. 

Q. What is the best proportion of length to 
diameter of mill shafting journals ? 

A, Four diameters in length. 



142 Practical Catechism. 

Q. How can you test lubricating oil for acid ? 

A. Koughly by shaking it with crystallized 
carbonate of soda dissolved in its own bulk of 
water. After continued shaking and standing 
there should be no sediment, or precipitate. If 
there is, it shows that there has been acid to 
drive off the carbonic acid and form a compound 
with the soda. 

Q. How may the composition of an oil be 
approximately determined by the figure that it 
produces upon water ? 

A. Each kind of oil produces a definite figure 
in a given time, if dropped upon the surface of 
perfectly clean water. Establish a standard by 
dropping perfectly pure olive, sperm, lard and 
other oils upon perfectly clean water, and then 
having carefully observed the patterns which 
they produce upon clean blotting paper, at 
once place the blotting paper upon the surface 
of water strongly colored with ink. Mark each 
sheet with the name of the oil which produced 
the pattern. Then make sheets for mixtures in 
various percentages of various oils ; and use 
these sheets as standards for comparison. Ab- 
solute cleanliness must be observed all through ; 
the oil dropped on the water from a glass rod 
which is at each test washed in soda and then 
in pure water and wiped dry. 



Practical Catechism. 143 

Q. What is the chlorine test for oils ? 

A. Animal oils are turned brown by chlorine ; 
vegetable oils are turned white. 

Q. How does pressure affect the coefficient of 
friction ? 

A. It lessens it up to a point where the press- 
ure is over five hundred lbs. per square inch. 

Q. What is the reason that crank pins will 
stand so much higher pressure per square inch 
than main bearings ? 

A. Because at each reciprocation of the en- 
gine there is a chance for the oil to work in be- 
tween the contacting surfaces. 

Q. Is there any greater friction of journals, 
etc., at the moment of starting than after they 
have been turning ? 

A. Yes; the friction of starting may be 
twenty times as great as that of continuous run- 
ning ; and thus must be considered as an addi- 
tional load on the engine, in addion to the in- 
ertia of the parts to be overcome. 

mechanical. 

Q. In a cylindrical or a flat bearing for a 
vertical shaft, where is the wear the greatest, and 
why? 



144 Practical Catechism. 

A. At or towards the circumference, because 
there the velocity is greatest. 

Q. How is it with a hemispherical bearing, 
the end of the shaft being rounded and working 
in a cup ? 

A. The same is the case, but not to the 
same extent, because the pressure towards the 
circumference is not at right angles to the 
surface, hence is proportionately less for that 
reason. 

Q. What would be the theoretically perfect 
bearing for vertical shafts ? 

A. One in which the curve would be such as 
to make the angles at which the pressure comes 
at any given distance from the axis, in proper 
proportion to the velocity at that distance. 
Such a bearing is made by the " Schiele curve," 
or " curve of the tractrix." 

Q. How may the Schiele anti-friction curve 
be traced ? 

A Draw the line BC at any length at the 
extremity of and perpendicular to AB. Take 
any number of points equidistant, 1, 2, 3, etc., 
on AB. Draw the line 1(7, and from 1 lay off 
the distance la equal to B C; a is a point in the 
curve. Next draw the line 2a, and set off 26 
equal BO. Continuing this, points will be es- 
tablished through which the curve may be 



Practical Catechism. 



145 



traced. The divisions of the line AB should 
be as numerous as possible. 




Fig. 4. — schiele antifriction curve. 



146 Practical Catechism. 

Q. How can a simple recording revolution 
counter be made — one that will do for high 
speeds and show irregularities in velocity ? 

A. A simple revolution counter, proposed by 
Gen. Meigs, is a pencil tied to the end of the 
shaft, and tracing a spiral curve on a sheet of 
card-board lightly pressed against it and trav- 
ersed, during a stated time. The coils of the 
spiral are counted at leisure. 

Q. " I wish to re-babbitt the boxes on a line- 
shaft, and as I never did any of that kind of 
work, I thought I would write you for instruc- 
tions how to do it, as I want to make a success 
of the job." 

A. Get a mandrel of the exact diameter of 
the shaft and a trifle longer than the bearings 
are to be. Wrap around it one thickness of 
good writing paper — leaving no lap or seam. 
Set the mandrel in the box, with a slip of card- 
board on each side, lying close along the man- 
drel and pinched by the halves of the box. 
These slips will divide the annular space be- 
tween the shaft and the box into two semi- 
annular spaces of practically equal dimensions. 
Buy good babbitt metal of a responsible firm 
and pay a good price for it, or else make it ac- 
cording to the formula given in any reliable 



Practical Catechism. 147 

technical book.* (Good bearing-metal cannot 
be made out of cheap and poor materials, nor 
by " hit and miss " formulas.) 

While the metal is melting in a ladle, build a 
bottom of mud about the ends of the box, and 
leave a pouring space in each division of the 
annular space between the shaft and the man- 
drel. Make a long tube of writing paper with 
a paper funnel at the top, for each pouring 
hole, and pour the metal with a long " riser " 
so that it will be driven by the head well into 
every crevice. Then break off the "sinking 
head " and open the boxes, and you will find 
them poured. 

Of course there must be an air vent for 
each side, at the top, alongside of the pouring 
hole. It may be desirable to " tin " the boxes 
before pouring ; but it is better to drill holes 
in the boxes so that the linings cannot turn in 
them. 

It is much better to use a mandrel than to 
pour around the shaft itself. 

The metal should be about hot enough to 
scorch writing paper; and when poured there 
should be no blow holes nor streaks ; every 
crevice should be thoroughly filled. 



* See page 13 of this work. 



148 Practical Catechism. 

Q. What seems to be the trouble in keeping 
ball and socket steam-joints tight ? 

A. The fact that although the ball and the 
socket have the same radius at start, the ball 
wears to a smaller radius and the socket to a 
larger one, so that they cannot possibly touch 
over any extended area, no matter how strongly 
they may be pressed together, any more than a 
ball would make good contact with a flat sur- 
face (which is practically a concave of infinite 
radius). 

Q. Is there any rule as regards the strength 
of piston rods, connecting rods and such other 
members as receive reciprocating strains ? 

A. They should be made from nine-fifths to 
double as strong as those which bear but one 
kind of strain. 

Q. How are hollow copper fire-box stays 
made? 

A. They may be made by drilling through 
solid rods, or by rolling sheet copper around a 
mandrel. 

Q. Give a recipe for making a solution so 
that when you screw a nut or a bolt it will 
never turn ? 

A. Use a "rust joint mixture "made of sal- 
ammoniac iron borings, flowers of sulphur, and 
water. 



Practical Catechism. 149 

Q. Suppose that there are three wheels upon 
one axle, all fastened tight and stationary ; the 
wheels upon each end being 6 feet in diameter 
and the center one 3 ; now if all these wheels 
are placed upon a treble track so that all wheels 
will bear alike ; in rolling will the small wheel 
slide as it revolves in order to keep in line with 
the large ones ? 

A. If the large wheels do not " skid " or 
slide, the small one will have to slip. If the 
small one does not slip, the large ones will have 
to skid or slide. It might be that some of the 
lost motion would be by the large ones skidding, 
a part of it by the small one slipping. 

Q. " We have a machine which has two very 
heavy worms driving worm wheels about eight 
(8) feet in diameter by twelve (12) inches face. 
As it is, there is considerable wear of the worm, 
and we wish to re-design the worm and wheel. 
At present the worm is two (2) inches pitch and 
sixteen (16) inches outside diameter, the shaft 
on which it is keyed being twelve (12) inches 
in diameter. The worm makes eighty (80) 
turns per minute and the work is very heavy. 
What would you advise ? 

A. As you do not state to the contrary we as- 
sume that the worm is of the ordinary cylindri- 
cal type ; that is, with parallel sides. In this 



150 Practical Catechism. 

case, particularly if the spur which it drives is 
not of very great diameter, there will be very 
little tooth surface in contact ; say no more than 
two teeth in full gear and two in half gear, at 
any one time. It would be better to make the 
worm of the " hour glass " type, so that there 
will be a greater number of teeth in gear with 
it at a time. In order best to cut such a worm, 
it is first rough-cut with a planer cutter 
having the exact profile of the teeth of the 
worm wheel and clamped to a radius bar at the 
exact distance from the center that the teeth 
will be on the real wheel ; this radius bar be- 
ing given, while the worm blank is rotated 
against the cutter, a relative motion correspond- 
ing to that of the wheel which is to gear with 
the worm, the latter is cut. Then a cutter 
being made corresponding to the worm, it and 
the wheel blank are rotated at the same relative 
velocity that the worm and the wheel are to 
turn, and thus the wheel is cut. Worm gearing 
cut under such circumstances cannot fail to gear 
together properly. For hour glass gearing it is 
about as well to give the worm threads plain 
straight inclined sides ; although if the work is 
all done in one direction and the gears are not 
to be reversed, the working side may be perpen- 
dicular so as to strengthen the worm threads. 



Practical Catechism. 151 

If the wheel is of cast iron the worm may be 
of phosphor bronze. 

Q. "A cotton compress has its platen drawn up 
by four hangers or links which when the platen 
is raised to its greatest height and the strain is 
the greatest, incline towards each other at their 
lower ends so that the pin centers at these lower 
ends are about a foot nearer together than those 
at the upper ends. At present there is hardly 
room enough at the bottom, between the links 
and the cotton bale, to permit the ties to be 
properly fastened. If the platen be lengthened 
so as to make the links vertical when the bale- 
is at its greatest compression, will the power of 
the machine be increased or diminished by 
reason of the more direct pull ? " 

A. The effect of the pull upon the links will 
be greater if they are parallel while their upper 
ends are being raised at right angles to the 
platen, than if their lower ends are inclined to 
each other. To prove this, increase the inclina- 
tion until the lower ends join and then the 
pull would be at right angles to the length of 
the links. 

Q. What is the proper way to polish alumin- 
ium ? 

A. Use a fine polishing composition of rouge, 
or tripoli, and a sheep-skin or chamois-skin 



152 Practical Catechism. 

buff; although it is often polished with an or- 
dinary rag-buff. 

For fine work, use a mixture of equal parts, 
by weight, of olive oil and rum, made into an 
emulsion by being well shaken together in a 
bottle. The polishing stone is dipped in this 
liquid and the metal is polished, without using, 
however, too much pressure. 

Q. How may aluminium be easily ground ? 

A. By using olive oil and pumice. 

Q. How may aluminium be engraved ? 

A. If the surface be treated with a varnish of 
four parts oil of turpentine to one of stearic 
acid, or with a mixture of olive oil and rum 
shaken to an emulsion, an engraving-tool will 
work on it as on pure copper. 

Q. What is the best way to burnish alumin- 
ium? 

A. Use a blood-stone or steel burnisher. For 
hand-burnishing, use either kerosene oil or a 
solution composed of two tablespoonfuls of 
ground borax dissolved in about a quart of hot 
water, with a few drops of ammonia added. 

For lathe work, the burnisher should wear 
upon the fingers of his left hand a piece of 
cotton flannel, keeping it soaked with kero- 
sene, and bringing it in contact with the metal, 
supplying a constant lubricant. 



Practical Catechism. 153 

Very fine effects can be produced by first bur- 
nishing or polishing the metal and then stamp- 
ing it in polished dies, showing unpolished fig- 
ures in relief. 

Q. How may aluminium be finished ? 

A. Polish or burnish the surface, and then 
use a fine steel scratch-brush. A very fine fin- 
ish is attained by rubbing with ground pumice- 
stone and water. 

Q. In spinning aluminium what precautions 
should be taken ? 

A. Plenty of oil should be used to prevent the 
clogging of the tool and to make it cut smooth 
in the turning, and to assist in the spinning. 

Q. " Please state what difference, if any, there 
is between a ( mechanical engineer ' and a ' ma- 
chinist and engineer ? ' " 

A. " Engineer" has got to mean almost any- 
thing. Those who are professional mechanical 
engineers here are called civil engineers in 
England and in France. There was a time 
when the machinist who made or helped make 
the parts of an engine, stationary, marine or 
locomotive, was selected to erect it and very 
often to run it. He then was a machinist and 
engineer. The man who runs an engine — that 
is starts and stops it, tends it, and adjusts it — is 
properly speaking an engine-runner; whether 



154 Practical Catechism. 

that engine be stationary, marine or locomotive. 
The iron worker who makes, or is one of those 
who makes, the iron work after it has left the 
hands of the blacksmith or foundry, is a ma- 
chinist. The man who designs it is in this 
country a mechanical engineer, and in England 
and in France a civil engineer. The man who 
makes the drawings from the sketches or speci- 
fications of the mechanical engineer is a drafts- 
man. He may be a mechanical engineer as 
well. The man who designs other machinery 
than steam engines is a mechanical engineer in 
this country, and a civil engineer in England 
and in France. In this country a civil engineer 
pays most attention to earth work, masonry, 
water power and problems of that kind. Some 
years ago, when the American Society of Me- 
chanical Engineers was started, it was proposed 
to call those who had to do with steam engines 
and other motors as designers and constructors, 
"dynamic engineers." Now-a-days the profes- 
sions are so lapped that it is hard to classify 
any one man as belonging to any one division. 

METALS. 

Q. What are the useful metals ? 
A. Iron, copper, lead, tin, zinc, antimony, 
bismuth, nickel and aluminium. 



Practical Catechism. 155 

Q. What are the relative tenacities of the 
useful metals? 

A. About as below : 

Lead 1 

Tin 1.3 

Zinc 2 

Cast iron 7 to 12 

Worked copper 12 " 20 

Wrought iron 20 " 40 

Steel 40 " 100 

Q. What is the order of ductility of metals ? 
A. Gold, silver, platinum, iron, copper, al- 
uminium, zinc, tin, lead. 

Q. What is their order of malleability ? 
A. Gold, silver, copper, tin, platinum, lead, 
zinc, iron, nickel. 

Q. What are the melting points of the most 
refractory metals ? 
A. 

Silver 1749° F. equals 954° C. 

Gold 1863° F. " 1017° C. 

Copper 1890° F. " 1032° C. 

Platinum. . ! . 3195° F. " 1957° C. 
Iridium 3510° F. " 1988° C. 

Q. What are the actual and relative expan- 
sions of zinc, lead and tin under heat ? 



156 Practical Catechism. 

A. Assuming the length to be one, the follow- 
ing figures give the expansion from deg. C. 
(32 deg. Fahr.) to 100 deg. C. (212 Fahr.): 

Zinc, hammered 00301 

Zinc 002942 

Lead 002848 

Tin 002840 

Zinc and tin 002692 

For higher temperatures this rate increases. 

Q. At what temperature is zinc malleable 
enough to roll ? 

A. About 120 deg. C. (equals 248 deg. 
Fahr.) ; and it must be kept just that hot all 
through ; as above that it is brittle, and below 
it there is too much resistance. 

Q. What is necessary to observe in making 
zinc castings ? 

A. That if made at a high temperature they 
are crystalline and brittle ; they must be cast 
near the melting point. 

Q. In what is lead soluble ? 

A. In water containing carbonic acid, or salts 
of nitric acid. 

Q. How is mercury purified ? 

A. By shaking with powdered sugar or char- 
coal. 

Q. Is platinum attackable by any ordinary 
chemicals ? 



Practical Catechism. 157 

A. Yes, carbon and silica corrode it. 

Q. How does aluminium behave in cold-roll- 
ing ? 

A. "In cold-rolling aluminium, upon rolls de- 
signed for cold-rolling hard crucible steel, it has 
been found possible to reduce aluminium 
through the same sections as hard steel; the 
aluminium required, on the average, five anneal- 
ings, where the steel required three to with- 
stand the same work satisfactorily ." 

Q. What are the specific weights of the vari- 
ous metals as compared with aluminium ? 

A. The specific gravity of aluminium being 
taken as one, soft steel is very nearly 2.95 times 
as heavy, copper 3.6 times as heavy, ordinary 
high brass 3.45 times as heavy, nickel 3.5 times 
as heavy, silver 4 times as heavy, lead 4.8 times 
as heavy, gold 7.7 as heavy. 

Q. What are the actual weights of aluminium 
compared with iron, steel, copper and brass ? 

A. 

A cubic in. of cast aluminium weighs 0.092 lb. 

A cubic ft. of cast aluminium weighs 158.967 " 

" soft steel weighs 490.450 " 

" wrought iron weighs 485.874 " 

" copper weighs 554.988 " 

" ordinary brass weighs. . ♦ 524.160 " 



158 Practical Catechism. 

Q. What are the properties of aluminium 
compared with cast iron ? 

A. Aluminium has about the tensile strength 
of cast iron, with only about one-third of its 
weight, and if properly handled casts equally 
easily and successfully, and can therefore be 
very advantageously used to replace cast iron in 
the parts of some classes of moving machinery 
that have to be reversed or otherwise have their 
momentum overcome ; for with one-third the 
weight there will be but one-third the momen- 
tum. 

Q. What is the melting point of pure alum- 
inium ? 

A. At about 1200 deg. Fahr. 

Q. What is the effect of impurities on the 
melting point ? 

A. It materially alters it ; thus one per cent, 
of iron raises it over 100 deg. 

Q. What are its characteristics in melting ? 

A. It does not remain firm like lead almost 
to the fluid point and then suddenly give way, 
but has a stage of from 1000 deg. Fahr. to 1200 
deg. Fahr. in which the metal becomes pasty, 
loses much of its power of cohesion, and during 
which stage, if the metal be gently pressed to- 
gether, it can be readily welded. It is, how- 
ever, very red-short at this temperature, and 



Practical Catechism. 159 

will not stand hammering to weld the metal, 
without crumbling down. If the metal is not 
too long a time in this pasty condition, it does 
not seem to become injured after being again 
cooled down. 

MILLWRIGHTING. 

Q. "What must be the dimensions of the 
sides of a triangular hopper in which the run 
and the rise are equal ? " 

A. That depends on what you call the run, 
and on what you call the rise. If you mean 
that the height of the hopper is equal to the 
length of one of the sides of the top, it can be 
figured out about as follows : — 

Draw three lines from the angles to the cen- 
ters of the sides, intersecting in the center of the 
top : the distance from each of the angles to the 
center will be two-thirds of the distance, and 
from the center of the sides to the center of the 
top will be one-third. Supposing the sides of 
the top to be 1 foot each, the distance across 
from the angle to the center of the side is equal 
to 41 s — .5*= V/75=.866. One-third of this is 
.2S9 (nearly) ; and two-thirds is .567 (nearly), 
the distance along the edge of the hopper ; that 
is the length of the sides in the joints is equal to 
Vl ,2 +.567 ,2 = Vl.3215=1.149. 



160 Practical Catechism. 

The contents of the hopper will be equal to 
the area of the base times one-third the height ; 
and as the area of the base is equal to the pro- 
duct of one. side by half the height of the tri- 
angle, or IX. 433 =.433, the volume of the hop- 
per will be equal to .433 X. 333=. 14433 cubic 
feet. 

Q. " Suppose that a three-sided hopper is to 
be made of sheet iron, and that the sides are to 
be made of pieces each of which is half a square 
one square foot on the side ; what will be the 
dimensions of the hopper in all its measure- 
ments, and how much will it hold? Please 
give the work." 

A. The hopper is to be a three-sided pyramid 
with equilateral base. Each side will be one 
foot along on each of those edges which are at 
right angles and Vl 2 +l s = V2= 1.4142 feet on 
its longer side. When the hopper is put to- 
gether (not allowing for joints) its top will be a 
triangle having each side 1.4142 feet. The 
height of each side will be VP— .7071*= V~5= 
.7071 foot. But this will not represent the 
height of the hopper. The distance from the 
center of any side to the opposite angle of 
the hopper, measured across the top, will be 
Vl.4142*— .7071*= VL5=1.2247. 

The distance from the center of the side of 



Practical Catechism. 161 

the top to the centre of the top is one-third the 
distance from the angle to the center of the 
side ; and the distance from the angle to the 
center of the top is two-thirds the distance from 
the angle to the center of the side. So we have 
for these distances 0.4082 and 0.8164 respectively. 

The rise is equal to W— . 8164*= V.3335 = 
.5 775; or it is equal to V.7071 8 — .4082*= 
V.5— .1665=.5775. 

The contents of the base will be 1.4142 X. 612 
=.8654; which multiplied by one-third the 
height of the pyramid gives .50185 cubic foot 
as the volume of the hopper. 



PAINTS, OILS AND VARNISHES. 

Q. What is the best way to prevent wrought 
iron from rusting ? 

A. A method, said to be both effective and 
cheap, for preserving wrought iron from rust 
after milling, is to first dip the article in hot 
soda water, to cleanse from oil, then in hot lime 
water, and dry. 

Q. How may files and other pieces of steel be 
kept from rusting over night ? 

A. By being placed in lime water. The lime 
may be perfectly removed by oil after drying 
with waste that has been used. 



162 Practical Catechism. 

Q. What is the best protection for bright 
work on machinery, in shipping ? 

A. It is better to use tallow and lime for 
bright work than white lead and tallow. In 
any case there should be an excess of tallow so 
that the covering may be readily wiped off with 
waste. 

Q. What is a good varnish for painting and 
glazing machinery? 

A. Thirty -five lbs. of shellac, five of Manila 
copal, ten of Zanzibar copal, and one hundred 
and fifty of potato spirit, made like the fore- 
going. 

Q. How may a lacquer for steel be made ? 

A. Of 10 parts of clear mastic, 5 of camphor, 
15 of sandarach and 5 of elemi gum dissolved in 
pure alcohol, filtered and applied cold. This 
varnish is transparent. 

Q. " How can I get a good durable black 
paint for smoke-stacks and boiler fronts — one 
which will not flake off nor blister ? " 

A. Apply with a piece of waste, " black 
lead " ground in linseed oil ; then sift over it 
ordinary black lead. To renew, use black lead 
(graphite, plumbago) stove polish. This is 
about the way they do it at the Hornellsville 
shops of the Erie Railway. 

Q. What harmless preparation can be used 



Practical Catechism. 163 

for coating a wooden tank, to supply a house 
with water, to prevent the water from penetrat- 
ing the wood ? 

A. Paint it inside with melted paraffine ap- 
plied hot, then burn in with a gasoline burning 
tool, such as painters use for burning off' old 
paint ; the heat will expand the pores of the 
wood, and the paraffine will enter, leaving the 
surface clean. Care should be taken not to apply 
the heat too suddenly, as the paraffine will run 
down before the pores are sufficiently open. 

Q. " What can I use to coat Manila paper, by 
dipping, to make it impervious to moisture ? It 
must be cheap, contain no poisonous ingredi- 
ents, not crack, nor deface the paper." 

A. Paraffine or wax is commonly used. 

Q. What will prevent the corrosion of iron 
tanks which are exposed to vapors and sulphur- 
ous gases ? 

A. Tar them or coat them with asphalt 
paint. 

Q. What will check the internal corrosion of 
the bottoms of iron ships where exposed to the 
action of bilge water ? 

A. Lime water. 

Q. What will partially prevent fouling and 
oxidation of the outside ? 

A. Solution of oxychloride of copper. 



164 Practical Catechism. 

Q. What is a good paint for ships' bottoms ? 

A. Colton proposes first to cover the vessel's 
bottom with two or three coats of red lead, let- 
ting each dry well before applying the next ; 
then melt in an iron pot a mixture of two parts 
beeswax, two of tallow and one of pine resin, 
mix thoroughly and apply hot one or two coats. 
This latter mixture may be tinted with ver- 
milion or chrome green. This acts by being 
soft and wearing off, thus preventing any accu- 
mulation. 

Another one is to mix red lead and granular 
metallic zinc ground fine, and put on two or 
three coats, letting each one set before putting 
on the next. This will never dry hard, but the 
zinc will wear off and keep the surface clean 
while the lead which remains will preserve the 
iron. 

The oil to be used for both these paints is 
linseed boiled as little as possible and thinned 
with spirits of turpentine. 

Q. What is a good thing to preserve the 
inside of steam boilers which are out of use for 
a long time ? 

A. Fish oil. 

Q. What are the materials used to preserve 
woods by saturation ? 

A. Kyan used Trichloride of mercury (corros* 



Practical Catechism. 165 

ive sublimate) ; Burnett, the chloride of zinc ; 
Boucherie, the pyrolignite of iron ; Margery, 
sulphate of copper, (blue stone, blue vitriol) ; 
Bethell, creosote ("dead oil" from gas works) ; 
Beer, solution of borax. 

Q. What is the best adhesive for gold leaf? 

A. Fatty oil, made by exposing linseed oil to 
the sun in a partly-corked bottle. It should be 
kept dry and left alone for a year. It must 
never be used under varnish. 

Q. How may tower clock dials be gilded to 
last the longest time ? 

A. By coating them with tin foil and gilding 
on that. 

Q. How can paint be made to stick to zinc ? 

A. By first using the following wash (recom- 
mended by Boettger) : — 

Chloride of copper 1 part 

Nitrate " " 1 

Sal ammoniac ." . . . 1 

Water • • • • 64 

This wash coat is to be left for 24 hours be- 
fore applying the paint. 

Q. Which stand the climate the best, other 
things being equal : — light or dark lead paints ? 

A. Dark, by reason of the lead "powder- 
ing." 



166 Practical Catechism. 

Q. What is the best preventive of lead pois- 
oning ? 

A. Drinking unskimmed milk in large quan^ 
tities daily, and also sour lemonade. The 
first feeds the body with fat to replace that 
saponified by the lead ; the second makes the 
lead that is in the blood more soluble. 

Q. How may the use of aniline colors in iron 
paints be detected? 

A. By burning the paint over an alcohol 
lamp, which will destroy aniline and leave the 
reddish iron in its natural color. 

Q. Why does white lead paint blacken when 
exposed to sewer gas ? 

A. Because the sulphur in the latter turns 
the carbonate of lead to sulphide, which is 
brown or black. 

Q. What is the proper kind of white paint to 
use where there is liability of blackening from 
sewer gas, etc. ? 

A, Zinc paint; the sulphide of zinc being 
white. 

Q. How can I make an absolutely black pig- 
ment? 

A. Treat gum camphor with strong sulphuric 
acid ; dilute with water to a thin liquid. Add 
chloride of barium to throw down the excess of 
sulphuric acid, and after settling, decant off the 



Practical Catechism. 167 

black supernatant liquid. If wanted dry, evap- 
orate to dryness. This pigment is blacker than 
Chinese black and not blue-black like ivory 
black. [W. H. Wahl.] 

Q. What is the true meaning of the expres- 
sion " covering power," as applied to a paint ? 

A. Ability to hide dark colors underneath it ; 
not spreading power, or ability to be extended 
over a great surface. Lead paints have better 
covering power than zinc paints, but the latter 
have the greater spreading power, that is, make 
the thinnest layers. 

Q. How can one test the true " covering 
power " of a white paint ground in oil ? 

A. Weigh 100 grains of the inspected sample 
and of a pure standard ; add to each 3 drops of 
linseed oil ; spread each sample evenly with a 
steel spatale over a 6x12 glass pane. Hold 
both panes to the light. The sample which 
shuts off the most light has the greatest " cover- 
ing power," used in the true sense of the word. 

Q. Why does varnish increase the brilliancy 
of colors under it ? 

A. By throwing the white rays of light out of 
the way and leaving the colored rays from be- 
low it less mixed with white light. It disposes 
of the strong surface light and thus gives a 
chance to the feeble rays from below. 



168 Practical Catechism. 

Q. What do varnish or paint cracks on wood, 
across the grain, show ? 

A. Poor materials or improper use of good 
ones. 

Q. What do paint or varnish cracks in the 
direction of the wood fibers, show ? 

A. That the wood has gained moisture. 

Q. What gives varnish its hardness and part 
of its durability ? 

A. The resin or gum. 

Q. What gives it elasticity ? 

A. The oil. 

Q. Which is it the more necessary to have of 
good quality ? 

A. The varnish. 

Q. What is the only objection to the use of 
much oil in varnish ? 

A. More skill is needed in making the var- 
nish and in using it coat over coat. 

Q. Will the action of air alone on seasoned 
wood, even if the air contains considerable 
moisture, cause it to rot ? 

A. No — as witness the woodwork of ancient 
churches and cathedrals in England. 

Q. What is the action on wood, of air con- 
taining not more than the usual moisture ? 

A. To swell and split it. 

Q. What is the first cause of decay in wood ? 



Practical Catechism. 169 

A. The presence of sap. 

Q. What next ? 

A. Dry rot is caused by the growth of little 
fungi which feed on the woody fiber. 

Q. What next? 

A. Paint, when the timber is unseasoned. 

Q. What next? 

A. Alternate wetting and drying. 

Q. What causes the whitening and loss of 
transparency in varnish on oil paintings ? 

A. Partial separation of the gum of the var- 
nish from the hard dried oil, owing to the 
evaporation of water which has been deposited 
by the air on the surface of the picture. 

Q. Which exposure is likely to cause this in 
the greatest degree ? 

A. Northern. In Munich 52 per cent, of the 
pictures in rooms with a northern exposure 
were thus affected ; only 10 per cent, of those 
with southern exposure. 

Q. Where does this happen most, in northern 
or in southern countries ? 

A. In northern countries where the air is 
damp and cold. 

Q. What are the principal combinations used 
in color-mixing ? 

A. Cream. — Chrome yellow, Venetian red 
and white lead. Pearl Gray, — W T hite lead, with 



170 Practical Catechism. 

equal proportions of Prussian blue and lamp- 
black. The blue must be used cautiously. 
Fawn. — Burnt sienna, ground very fine, mixed 
with sufficient white lead. Buff. — Pale chrome 
yellow and white lead, tinged with a little Ven- 
etian red. Straw. — Pale chrome yellow and 
white lead. Drabs. — Raw or burnt umber and 
white lead, with a little Venetian red ; or, white 
lead, with a little Prussian blue and yellow 
ocher ; or, white lead, with a little yellow ocher 
and lampblack; or, white lead, with a little' 
chrome green. Purples. — White lead, Prussian 
blue and vermilion ; or, Prussian blue, vermil- 
ion and rose madder, or crimson lake. Violet. 
— Vermilion, French ultramarine, and a small 
quantity of lampblack and white lead. Silver. 
— White lead, indigo, and enough black to give 
the desired shade. Dark Chestnut. — Mix red 
and black. Use red ocher when required to 
lighten the color. Salmon. — White lead, tinged 
with Venetian red. Peach Blossom. — White 
lead, tinged with orpiment. Lead. — A suitable 
mixture of black and white lead. Dark Lead. — 
White, black and indigo. Chocolate. — Vegetable 
black and Venetian red. Light Yellow. — Lemon 
yellow and white lead ; or, chrome yellow, 
white lead and red lead ; or, raw sienna mixed 
with white lead, with the addition of a little 



Practical Catechism. 171 

burnt sienna if the tint is required to be warmer. 
Stone. — Yellow ocher, burnt umber and white 
lead; or, raw sienna, burnt umber and white 
lead ; or, white lead, burnt umber, yellow ocher, 
and a little Venetian red. Olive Green. — Prus- 
sian blue, chrome yellow and burnt umber ; or, 
vegetable black, chrome yellow, and a little 
burnt umber. Grass Green. — Prussian blue and 
chrome yellow, in proper proportions. Carna- 
tion. — Lake and white lead. Old Gold. — White 
lead, chrome yellow, and burnt sienna until the 
right shade is obtained. 

Q. How is " distemper " made ? 

A. 112 lbs. whiting, 28 lbs. dry white lead, 7 
lbs. glue, mixed with boiling water. 

Q. How is boiled oil made ? 

A. To 103 parts of raw linseed oil add 3.15 
of copperas (sulphate of iron, green vitriol,) and 
6.3 of litharge. Put the two latter in a cloth 
bag and suspend in the oil ; boil 4J hours 
with a slow steady fire. 

Q. How is dryer or drying made ? 

A. To 60 parts of copperas and litharge from 
the boiled oil add 56 of spirits of turpentine and 
2 of boiled oil, grinding and thoroughly mix- 
ing. 

Q. With what kind of oil should putty be 
made, if not to be used at once ? 



172 Practical Catechism. 

A. With raw oil, as that made with boiled 
oil hardens rapidly. 

Q. What is a good mixture for filling cracks 
in woods instead of putty ? 

A. Mix finely sifted or ground oak sawdust 
with linseed oil which has been boiled until it 
has become glutinous. 

Q. Of what is putty made ? 

A. It should be made of Spanish whiting and 
linseed oil. It generally is made of poorer and 
cheaper things. 

Q. What is whiting ? 

A. Chalk in very fine powder. 

Q. What is " panel putty ? " 

A. Whiting, white lead in oil, japan (or 
varnish) and a small quantity of turpentine. 
When dry it can be rubbed down with pumice 
stone, or with sand paper. 

Q. What is glycerine putty ? 

A. Good thick glycerine and white lead or 
litharge ; it hardens in 15 to 45 minutes, and 
withstands water and acids. It is best used 
warm. 

Q. What is water glass putty ? 

A. Water glass (silicate of soda) and zinc 
white ; highly recommended as a putty for 
iron. 



Practical Catechism. 173 

Q. " What use is there in ' filling' wood ? Why 
not go right ahead and paint or varnish ? " 

A. The " filler " is generally cheaper than the 
paint or the varnish ; and, furthermore, it will 
enter the pores better. It is generally more 
easily applied. 

Q. What are the increases of measurements 
of various kinds of wood when thoroughly sat- 
urated with water ? 

A. The following table, from French experi- 
ments, gives the increases per hundred units of 
measure : — 

Wood. Length. Breadth. 

Maple 0.072 3.350 

Apple 0.109 3.000 

Birch 0.222 3.860 

Pear 0.228 3.940 

Beech, white. 0.400 6.660 

" purple 0.200 5.030 

Box 0.026 6.020 

Cedar 0.017 1.300 

Ebony 0.010 2.130 

Oak, young 0.400 3.900 

" old 0.130 3.130 

Ash, young 0.821 4.050 

" old 0.187 3.84 

Fir-wood 0.076 2.410 



174 



Practical Catechism. 



Q. What is the percentage of shrinkage of 
various green woods ? 

A. Karmarsch gives the following as the re- 
sults of German experiments : — 

AMOUNT OF SHRINKING OF GREEN WOOD 
IN PERCENTAGES. 



Kind of 
Wood. 


In length.* 


Cross Section. 


Directly 
through.f 


In directionof 
yearly rings. J 


Maple 

Pear 

Beech (red) . . 
Oak 


0.062 to 0.200 

2 228 

0.20 to 0.34 

0.028 to 0.435 

0.187 to 0.821 

0.076 
0.008 to 0.201 
0.013 to 0.288 

0.110 

0.223 
0.068 to 0.62 
0.086 to 0.122 
0.014 to 0.63 


2.0 to 5.4 
2.9 to 3.94 
2.3 to 6.0 

1.1 to 7.5 
0.5 to 7.8 

1.1 to 2.8 
0.6 to 3.8 
0.3 to 7.3 

1.09 

2.6 to 8.2 

1.2 to 4.2 

1.7 to 4.82 
1.2 to 4.6 


4.13 to 7.3 
5.5 to 12.7 
5.0 to 10.4 
2.5 to 10.6 


Ash 


2.6 to 11.8 


Pine (pitch) . . 
Fir 


2.0 to 7.3 
2.0 to 6.8 


Larch 

Mahogany . . . 

Walnut 

Poplar 

Pine (white) . 
Elm 


1.4 to 7.1 
1.79 

4.0 to 17.6 
2.8 to 9.8 

4.1 to 8.13 
2.7 to 8.5 







Q. How may old varnished oil paintings 
which have become dull, be restored without 
danger, to their original state ? 

A. By exposing the picture to an atmosphere 



* Parallel with length of fibers. Average -^ per cent. 

f From center to circumference of tree. Average 5 
per cent. 

% At right angles to other two measurements. Aver- 
age 10 per cent. 



, 



Practical Catechism. 175 

saturated with vapor of alcohol at ordinary tem- 
perature (without applying heat) so that the 
resinous particles of the picture absorb alcohol 
from that atmosphere until they are saturated. 
Thus the varnish-molecules which were separa- 
ted from each other, re-acquire cohesion with 
each other, and the original optical effect of the 
varnish is restored. The process is carried on 
by putting the picture face downward on a shal- 
low tray containing alcohol. [Pettenkofer.] 

Q. How should a fine carriage be kept ? 

A. The room should be dry, moderately dark, 
well ventilated, and perfectly free from dust. 
The carriage should be covered (when dry) with 
a dry cotton or linen cover ; and should be 
washed frequently (even when not in use) in 
the shade, with cold water and no soap. The 
sponge and the " shammy " should not be used in 
the same water; no part of the surface should dry 
before wiping with the shammy. 

Enamelled ("patent") leather, when new, 
should not be washed, but dusted, then wiped with 
a moist shammy ; dimming may be cured with a 
sponge wet in suds of soft water and soap, dry- 
ing with a shammy moistened in clean water. 
Hardened patent leather may be rubbed with 
neat's-foot oil ; spots removed with linseed oil 
on cotton waste and the oil then removed with 



176 Practical Catechism. 

castile soap suds. Koll-up curtains and aprons 
should be unrolled and stretched smooth ; cloths 
and cushions beaten ; morocco leather cleaned 
with a moist shammy. Mountings should be 
cleaned with rotten stone ; lamps with whiting 
and alcohol. A new carriage should be fre- 
quently washed. Carriages should be re-var- 
nished yearly ; if English varnish has been used 
originally it should be used for all subsequent 
coats. 

Q. What is a good varnish for walls ? 

A. One gallon white dammar varnish, five 
ounces of white wax, one half gallon of turpen- 
tine ; dissolve the wax in a steam-kettle to avoid 
darkening it, and when completely dissolved, 
add the turpentine. Let the mixture cool some- 
what, and add the dammar varnish. If the var- 
nish, when tried, is too glossy, add more wax. 

The wax offsets the brittle quality of the dam- 
mar gum, and if sufficient be used, no gloss will 
remain. A wall properly treated will last many 
years, with no change of color. Prime the wall 
with pure pil, without addition ; on this place 
four coats of the color, flat, over which lay the 
varnish. All necessity for stippling or mend- 
ing is avoided ; laps or brush-marks will disap- 
pear in a few days. The varnish may be used 
as color and varnish if preferred. 






Practical Catechism. 177 

Q. Is there any regular rule as to the quality 
of sunlight coming from the various points of 
the compass? 

A. "The north light is whitish to bluish; 
the south light has the yellow and purple, 
morning and evening tones, and the glare of 
noonday; the east and west lights have the 
yellow and purple but a little while, the morn- 
ing glow being followed by the bright dispersed 
light of the day, the evening gold and purple 
by the gray twilight." 

Q. What are the comparative rates of rusting 
of cast iron, wrought iron, and steel ? 

A. Cast iron least, wrought iron 25 per cent, 
faster, steel a third faster. 

Q. How can rusting of iron be prevented ? 

A. (1). By "galvanizing" or coating the iron 
with zinc (applied in a bath) ; (2) by tinning ; 

(3) by coating with lead or with lead and tin ; 

(4) by coppering ; (5) by painting ; (6) " Barff- 
ing " or treating with superheated steam or with 
very hot air, so as to form a coating of the brown 
peroxide of iron. 

Q. What is the weight of water at various 
convenient temperatures ? 

A. 
At 32° F. or 0°C. 1 cu. ft. weighs . 62.418 lbs. 
" 39°.l F. " 4° 62.425 " 



178 Practical Catechism. 

At 62° F. " 16.66° (stand, temp.) 62.355 lbs. 
"212° F. " 100° 59.640 " 

The weight of 1 cubic inch of water is, 

At 32° F. .03612 lbs. or 0.5779 oz. 
" 39°.l F. .036125 " " .5780 " 
" 62° F. .03608 " " .5773 " 

or 252.595 grs. 
" 212° F. .03451 " " .5522 oz. 

The volume of 1 pound of pure water is as 
follows : 

32° F. =.016021 cu. ft. or 27.684 cu. in. 
39°1 F.=.019019 " " 27.680 " 
62° F. =.016037 " " 27.712 " 
212° F. =.016770 " " 28.978 " 

The volume of one ounce of pure water at 
62 deg. Fahr. is 1.732 cubic inches. 

Q. How is prepared chalk made ? 

A. By adding a solution of carbonate of soda 
to a solution of chloride of calcium so long as a 
precipitate is thrown down. 

Q. How may a good preparation for waxing 
floors be made ? 

A. The following is recommended by the 
American Druggist : — 



Practical Catechism. 179 

Yellow Wax 25 oz. 

" Ceresin 25 " 

Burnt Sienna 5 " 

Boiled Linseed Oil 1 " 

Oil of Turpentine 30 " 

Melt the wax and ceresin at a gentle heat, 
then add the sienna previously well triturated 
with the boiled linseed oil, and mix well. When 
the mixture begins to cool add the oil of turpen- 
tine, or so much of it as is required to make a 
mass of the consistence of an ointment. 

Yellow ceresin is purified ozokerite (fossil 
paraffin), and may be had in almost any quan- 
tity. 

The burnt sienna may be used in smaller or 
larger quantity, according to the tint desired, or 
may be replaced by raw sienna, etc. 

Dieterich recommends the following : 

To 400 parts of boiling water add 200 parts of 
yellow wax ; when this is melted, add 25 parts 
of carbonate of potassium, boil for a moment or 
so, then remove the vessel from the fire and add 
30 parts of oil of turpentine. Stir until cool, 
and dilute with water to make 1000 parts. 

If the floors are well preserved, the dilution 
may be carried to 1500. 

The object of the potassium salt is to form an 
emulsion with the wax. 



180 Practical Catechism. 

Q. "I want to finish a house inside with 
Georgia yellow pine and white or spruce pine 
doors and sashes. The yellow pine I want to 
finish with oil, so as to bring out the native 
grain, and the doors and sash I wish to stain, 
say, dark cherry or mahogany. What stains 
and finishes shall I use ? 

A. The following is a commonly employed 
oil finish : — Linseed oil 16 ounces, black resin 4 
ounces, vinegar 4 ounces, rectified spirits 3 
ounces, butter of antimony 10 ounces, spirit of 
salts 2 ounces. Melt the resin, add the oil, take 
it off the fire, and stir in the vinegar, let it boil 
for a few minutes, stirring it ; when cool, put it 
into a bottle, add the other ingredients, shaking 
all together. For dark mahogany, introduce in- 
to a bottle 15 grains alkanet root, 30 grains aloes, 
30 grains powdered dragon's blood, and 500 
grains 95 per cent, alcohol, closing the mouth 
of the bottle with a piece of bladder, keep 
it in a warm place for three or four days, 
with occasional shaking, then filtering the 
liquid. The wood is first mordanted with nitric 
acid, and, when dry, washed with stain once or 
oftener, according to the desired shade; then 
the wood, being dried, is oiled and polished. A 
cherry stain is readily made by adding 4 ounces 
annatto to 3 quarts rain water ; boil in a copper 



Practical Catechism. 181 

kettle till the annatto is dissolved ; then put in 
a piece of potash the size of a walnut, keep it on 
the lire about half an hour longer, and it is 
ready to bottle for use.' 

Q. " Is there any substitute for linseed oil 
and lead as a cheap and durable paint ? What 
I want is a cheap and durable white paint for 
buildings. Some years ago I think I saw in 
the Artisan a recipe for such a substitute, but I 
have failed to find it." 

A. There are many substitutes for linseed oil 
and lead, some better and some not so good, 
according to the purposes for which they are 
intended. It is best to paint zinc with zinc 
oxide and iron with iron oxide. There are 
very few substitutes for linseed oil that are good 
for inside house work. For roofs and fences fish 
oil is an excellent menstruum in which to grind 
up the covering substances. For floors 5 lbs. 
of French ochre, \ pound of glue, and 1 gallon 
of water (hot) answers well ; one or two coats of 
linseed oil being applied when the paint is well 
dried. A reddish brown paint for wood is made 
by washing the wood with a solution of 1 pound 
cupric sulphate (sulphate of copper, blue vitriol, 
blue stone) in one gallon of water, and then 
with J pound potassium cyanide dissolved in 
one gallon of water. This is to be varnished 



182 Practical Catechism. 

afterwards with linseed oil varnish (not linseed 
oil). Finely precipitated silica ground in water 
glass (of soluble silicate of potash) is a good 
paint. Iron oxide ground in water glass and 
the same ground in fish oil are largely used 
for roofs and fences. 

Q. How can a fireproof whitewash be made ? 

A. The English Mechanic says : — It is found 
that a most effective composition for fireproof- 
ing exterior surfaces may be formed by slaking 
a sufficient quantity of freshly burned quicklime 
of the best grade, and when the slaking is com- 
plete there is added such an amount of skim 
milk, or water in its absence, as will make the 
liquid of the consistency of cream. To every 
10 lbs. of this liquid is added separately and in 
powder, stirring constantly, the following in- 
gredients, in the order named : 2 lbs. alum, 24 
ounces of sub-carbonate of potassium, or com- 
mercial potash, and 1 pound of common salt. 
If white paint is desired, a further addition is 
made to the liquid, though the whiteness is 
found to be improved by a few ounces of plaster 
of Paris. Lamp black has the effect of giving 
it a number of shades from slate color to black. 
Whatever tint is used it is incorporated at this 
stage, and the whole, after being strained 
through a sieve, is run through a paint mill. 



Practical Catechism. 183 

When ready to apply, the paint is heated 
nearly to the boiling point of water, and is 
put on in its hot condition. It is found that 
the addition of a quantity of fine white sand 
to this composition renders it a valuable 
covering for roofs and crumbling brick walls, 
which it serves to protect. 

Q. How is " everlasting " whitewash made ? 

A. Some years ago the following whitewash 
was used on the east end of the White House, 
and proved practically "everlasting." Take 
one half bushel of unslaked lime, slake it with 
boiling water ; cover it during the process to 
keep in the steam. Strain the liquid through a 
fine sieve or strainer, and add to it a peck of salt, 
previously dissolved in warm water, 3 lbs. of 
ground rice, boiled to a thin paste, J pound of 
of powdered Spanish whiting, and 1 pound of 
clean glue which has been previously dissolved 
by soaking it well, and then hang it over a slow 
fire in a small kettle within a larger one filled 
with water. Add 5 gallons of hot water to the 
mixture, stir it well, and let it stand for a few 
days covered from dust. It should be put on hot 
and for this purpose it can be kept in a kettle 
on a portable furnace. It is said that about a 
pint of this mixture will cover a square yard 
upon the outside of a house if properly applied. 



184 Practical Catechism. 

Fine or coarse brushes may be used, according 
to the neatness of the job required. It answers 
as well as oil paint for wood, brick, or stone, 
and is cheaper. It retains its brilliancy for 
many years. There is nothing of the kind that 
will compare with it, either for inside or outside 
walls. Buildings or fences covered with it will 
take a much longer time to burn than if they 
were painted with oil paint. Coloring matter 
may be put with it and made of any shade de- 
sired. Spanish brown will make a reddish pink, 
when stirred in, more or less deep, according to 
the quantity. A delicate tinge of this is very 
pretty for inside walls. Finely pulverized 
common clay well mixed with Spanish brown, 
makes a reddish stone color; yellow ochre 
stirred in makes yellow wash, but chrome goes 
further, and makes a color generally esteemed 
prettier. It is difficult to make rules because 
tastes differ. It would be best to try experi- 
ments on a shingle and let it dry. Green must 
not be mixed with lime ; it destroys the color, 
and the color has an effect on the whitewash 
which makes it crack and peel. 

Q. Give directions for making calcimine, 
(white and colored) ? 

A. Soak one pound of white glue over night ; 
then dissolve it in boiling water, and add 



Practical Catechism. 185 

twenty pounds of Paris white, diluting with 
water until the mixture is of the consistency of 
rich milk. To this any tint can be given that 
is desired. 

Lilac. — Add to calcimine two parts of Prussian 
blue and one of vermilion, stirring thoroughly, 
and taking care to avoid too high a color. 

Gray. — Raw umber, with a trifling amount 
of lampblack. 

Rose. — Three parts of vermilion and one of 
red lead, added in very small quantities, until a 
delicate shade is produced. 

Lavender. — Make a light blue, and tint it 
slightly with vermilion. 

Straw. — Chrome yellow, with a touch of 
Spanish brown. 

Buff. — Two parts spruce, or Indian yellow, 
and one part burnt bienna. 

PLANTS.* 

Q. What are the processes which occur with 
plant leaves, as regards carbonic acid ? 

A. The gas is taken in by the leaves during 
the daytime only ; at night a very little is taken 
in. The process during the daytime is the re- 
verse of that during the night. 

*See also under Trees. 



186 Practical Catechism. 

Q. Then is it healthy to have plants in a 
sleeping room ? 

A. No, unless very well ventilated. 

Q. What tree contains the least organic mat- 
ter known ? 

A. The cinnamon tree of Colombo in Ceylon 
contains only one per cent. 

Q. How may dahlias and other flowers be 
darkened ? 

A. Putting charcoal in the soil will darken 
dahlias, roses, and petunias. 

Q. How may red hydrangeas be darkened to 
blue? 

A. By peat. 

Q. How may hyacinths be reddened ? 

A. By carbonate of soda. 

POWER.* 

Q. What are the items which enter into the 
cost of steam power ? 

A. Interest on the cost of engine, boiler, 
chimney, boiler room and engine room ; wages 
of engineer and fireman ; insurance ; taxes ; a 
portion of the wages of general foreman and 
manager, repairs ; sinking fund for redemption 
of cost of boiler and engine. 



*See also under Belts, Gear Wheels, Shafting and 
Work. 



Practical Catechism. 187 

Q. What is the proportion of a man power to 
a horse power ? 

A. That depends upon how the man applies 
his power and for how long he has to apply it ; 
also upon whether you compare man power 
with the ordinary conventional horse power of 
33,000 lbs. elevated one foot high in a minute, 
or with the actual work of an average horse. 

A well fed and well treated horse weighing 
half a ton can pull with a traction of 100 lbs. at 
the rate of 2 J miles an hour, for ten hours, upon 
a tow path ; or he can exert a traction of 200 
lbs. for live hours at the same rate upon the 
same road ; or he can pull 125 lbs. at the rate 
of 2 miles an hour for ten hours, upon the same 
road. The useful paying daily net work of a 
horse in hoisting by a common gin, is about 
10,000,000 foot lbs. 

Now you have the two standards of horse 
power ; the actual and the conventional. 

A practiced laborer hauling along a level 
road by a rope over his shoulders can do about 
J as much as the horse ; but if he is turning a 
crank, so that he has to bend his body, etc., he 
can do only about 115,200 foot lbs. per hour of 
time including rests ; and there will be a loss 
also by reason of the friction of the machinery, 
which will bring his work down to just jq of 



188 Practical Catechism. 

what a horse will do. On a treadmill a man 
will do 40 per cent, more than at a crank ; that 
is, in ten hours, including rests, he will do 
about 1,400,000 foot lbs. By a good common 
pump, a man can in ten working hours raise , 
1,000,000 foot lbs. of water, net. By walking 
backwards and forwards on a lever which rocks 
on its center he can do more than by any of the 
modes before mentioned; Kobison quoting his 
work done in this way as nearly t 4 q of the net 
daily work of a horse in a gin. 

Q. How can one figure the number of times a 
crane handle will have to be turned for every turn 
of the chain barrel to hoist a certain weight ? 

A. Multiply the weight (in lbs.) by the diam- 
eter of the chain barrel (in inches) and divide 
by the diameter of the circle described by the 
handle (in inches), and by the power on the 
handle (in pounds). Thus: — suppose weight 
1000 lbs. ; barrel 10 inches, crank 16 inch ra- 
dius =32 inch diameter of circle, and power of 
one man on the handle in lbs., 20; then the 
crank must make (1000xl0)-s-(32x20)=10,000 
-=-640= 15.59 turns for every one of the barrel, 
or practically 16 to 1. 

Q. How much force can a good stout laborer 
apply at the end of a crane handle, right along 
all day ? 



Practical Catechism. 189 

A. Depends on the speed with which he 
works. A stout laborer can exert 10 lbs. at the 
handle, raising 1030 lbs. 16J feet in 1.5 min- 
utes=ll,550 foot lbs; or 15 lbs. raising 1575 
lbs. 16 J feet in 2.25 minutes^ 11,505 minute 
foot lbs. One man " with the utmost difficulty/' 
raised 3675 lbs. 16 J feet in 2.2 minutes by exert- 
ing 35 lbs. at the handle ; thus exerting 27,562 
minute foot pounds ; and another, also with the 
utmost difficulty, raised the same weight the same 
distance in 2.5 minutes, thereby exerting 24,255 
minute foot lbs. . You can generally figure on a 
good stout man averaging about ^q horse power 
for eight or ten hours. 

Q. Could power be transmitted by rarefied 
air? 

A. Yes, but what is the use? You could 
only get fifteen lbs. per square inch pressure, as 
a maximum, if everything was perfect. 

SHAFTING. 

Q. What is the rule for finding the maxi- 
mum twisting stress that may be transmitted by 
a shaft within good working limits ? (Twisting 
stress counted as the product of the actual tor- 
sional force in pounds, multiplied by the radial 
distance in feet at which it is applied.) 



190 Practical Catechism. 

A. Multiply the cube of the diameter in in- 
ches by 18.5 for cast iron ; by 27.7 for wrought 
iron ; or by 57.2 for steel. The product is the 
torsional stress in statical foot pounds. 

Q. What is the rule for finding the diameter 
of a shaft capable of transmitting a given twist- 
ing stress, within good working limits ? 

A. Divide the torsional stress in statical foot 
pounds by 18.5 for cast iron ; by 27.7 for 
wrought iron ; or by 57.2 for steel. The cube 
of the quotient is the diameter in inches. 

Q. What is the rule for finding the maxi- 
mum horse power of a shaft, within good work- 
ing limits ? 

A. Multiply the cube of the diameter in in- 
ches by the speed in turns per minute ; and di- 
vide by 285 for cast iron, by 190 for wrought 
iron, or by 92 for steel. The quotient is the 
horse power. 

Q. What is the rule for finding the diameter 
of a shaft capable, within good working limits, 
of transmitting a given horse power ? 

A. Multiply the horse power by 285 for cast 
iron, by 190 for wrought iron, or by 92 for 
steel ; and divide by the speed in turns per min- 
ute. The cube root of the quotient is the diam- 
eter in inches. 

Q. How is one to find the speed required for 



Practical Catechism. 191 

transmitting a given power, within good work- 
ing limits ? 

A. Multiply the horse power by 285 for cast 
iron, by 190 for wrought iron, or by 92 for 
steel ; and divide the product by the cube of the 
diameter in inches. The quotient is the speed 
in turns per minute. 

Q. How much power can a three-inch shaft 
carry ? 

A. That depends on the speed at which it is 
run, and whether it is a first, second or third 
mover. At 100 turns per minute a 3-inch 
(nominal diameter) shaft will carry 26 horse 
power, if it is the shaft next the engine ; 54, if 
the second ; and 81, if the third. 

RAILWAYS.* 

Q. How can you set the rails of a railroad 
track the proper distance apart, no matter what 
the temperature may be at the time of laying ? 

A. Have a tapered gauge of steel, which has 
such a taper as to correspond to the coefficient 
of expansion for temperature of iron or steel, 
whichever the rails are of. Let the widths 
across this taper, and its graduation marks be 
such that when it is forced in the space between 



* See also under Locomotives. 



192 Practical Catechism. 

the rails, up to the zero mark, that will be the 
right distance for that temperature; and that 
when it is only forced up to the 100 degree 
mark that will be the distance part for that 
temperature ; and so for intermediate and other 
points. 

Q. What will make railroad rails last the long- 
est, porous ballast or that which is not porous ? 

A. That which is porous. 

Q. What is the life of a Bessemer rail ? 

A. Of course that depends upon the traffic ; 
but taking things as they are, and without stat- 
ing the conditions, it may be said that in Ger- 
many the mean life is sixteen years. 

Q. What is the comparative life of iron and 
steel rails ? 

A. 10 years trial in Germany show that dur- 
ing that period the renewals were 76.7 per cent, 
of the rails of iron of fine grain, 63.3 of those of 
cementation steel, 33.3 those of puddled steel, 
and 3.4 per cent, of Bessemer. 

Q. What is about the relative train length of 
1000 tons of freight in ten -ton cars and in 
thirty ? And how about the weight of the cars 
themselves ? 

A. 1000 tons in ten-ton cars will take up 
3100 feet of length, while the same weight in 
thirty-ton cars take up only 1440 feet. As to 



Practical Catechism. 193 

the weight, the cars would weigh about 1000 
tons in the first case and about 412 in the sec- 
ond. 

Q. How may the speed of a train be deter- 
mined by a passenger ? 

A. A rule was recently contributed to Engin- 
eering by a professor in the Polytechnic School 
at Prague, for readily determining the speed of 
a train by counting the revolutions of the 
drivers, which has a certain convenience, and is 
as follows : 

Count the revolutions for a number of seconds 
equal to 2-11 of the diameter of the drivers in 
inches. The number of revolutions counted 
will be the speed in miles per hour. 

For example, if the drivers be fifty-five inches 
in diameter, 2-11 of fifty-five is ten ; and if 
twenty-four (or any other) number of revolu- 
tions are counted in that number of seconds, the 
speed is that number of miles per hour 

ROPES. 

Q. How are the strands of rope laid up ? 

A. Small cordage is usually composed of 
three (sometimes four) strands of yarns, laid up 
with a right hand twist ; each of the strands 
being laid up with a left hand twist. 

Q. How are hawsers laid up ? 



194 Practical Catechism. 

A. With three right hand strands. 

Q. How are cables laid up ? 

A. With three hawsers laid up left handed. 

Q. How are shrouds laid up ? 

A. With a central cord, surrounded by four 
strands. 

Q. What is the effect of tarring upon the 
strength of cordage ? 

A. To diminish it one-fourth. 

Q. What is the effect of increase of diameter 
upon the strength per square inch of cordage ? 

A. The larger sizes are weaker in proportion 
than the small ones. 

Q. What is the influence of the number of 
strands upon the strength of cordage ? 

A. Three strand cordage is 10 to 15 per cent, 
stronger than four strand, if rope laid ; 10 per 
cent, weaker in hawsers and cables. 

SAWS. 

Q. Which is the best set for circular saws ; 
spread or spring ? 

A. Spread. 

Q. What is the advantage of using thin saws ? 

A. They save lumber, time and power. 

Q. What is the merit of inserted teeth in cir- 
cular saws ? 

A. They save files and time. 



Practical Catechism. 195 

Q. Where should saw blades be thinnest? 

A. At the back. 

Q. What should be the speed of circular saws ? 

A. 9000 to 13,000 feet a minute, rim speed. 
For 9425 feet this will make a 36 inch saw run 
1000 turns ; a 48 inch, 750 ; 60 inch, 600 ; 72 
inch, 500. 

Q. What is the advantage of " two-high " cir- 
cular saws ? 

A. They save saws, time, lumber, labor and 
power. 

Q. What class of tooth should be given for 
soft wood ? 

A. Deeper teeth and more gullet than for 
hard. 

Q. What influence has the tooth rake on the 
cut? 

A. The more rake, the faster and rougher the 
cut. 

Q. What is the saving by narrow kerf? 

A. Every -^ inch kerf wood makes 1000 feet 
of lumber in every 16,000 sawed. 

Q. What class of teeth is needed for each 
class of material ? 

A. Metals, bone, and hard fine grained woods 
take small teeth and little or no set: ice and 
soft grained woods, large widely spread teeth, 
and much set. 



196 Practical Catechism. 

Q. Is there such a thing as a band saw that 
can be detached like a laced belt ? 

A. There is a method proposed, of joining 
the two ends by hooked and bevelled edges, but 
it has not been proved successful. 

Q. " How much tension would there be upon 
a 2J inch band saw blade, of 20 gauge, running 
about 1 mile a minute in an 18 inch cut ? " 

A. About 1,000 to 1,250 lbs. 

Q. " Our shingle saw bothers me. I cannot 
get the pitch to keep it any length of time. 
Will you give me a rule for this ? " 

A. "Pitch" is sometimes misused for the 
space or distance between tooth-points. If this 
is what you mean, of course you must expect 
the " pitch " to lessen as the saw gets smaller. 
If, also, this is what you mean, and you find the 
tooth-distances getting irregular, it is a sign of 
careless filing and gumming. Scribe a circle on 
the face of the saw, just inside the tooth gullets, 
and concentric with the tooth-points. Carefully 
step this off into as many equal spaces as there 
are teeth ; then scribe radial lines through the 
points of division, clear out to the rim ; and 
gradually file and gum the teeth down so that 
all shall be the same, front and back, and all 
parts come the same distance from a radial line. 
You can get the front and back just alike on all 



Practical Catechism. 197 

the teeth by using a regular emery wheel gum- 
mer ; if you have not one, make a sheet zinc 
template to correspond with what you want, 
and fit it to a radial arm of thin board which 
has a circular crotch made to straddle the 
collar. 

If by "pitch" you mean the angle of the 
front of the tooth — and that is its proper defini- 
tion — then the sheet zinc template fixed to the 
radial arm will fit you out completely if you 
have no regular gumming machine. 

What is the capacity of a band saw-mill, day 
in and day out ? 

A. The following figures show the capacity 
of a bandsaw-mill (that of C. Lamb & Sons, 
Clinton, Iowa). 

The first run reported was at mill C : 

Friday, Oct. 16, 59 Logs, 31,323 ft, )_ „ _ Q . 

o + i « 1- re u ononft f Full Log Scale, 

Saturday," 17,66 M 31,139 ft.) ° ' 

or, 16, - 39,153 ft. Lumber cut into 1, 1%, and 2 in. 

17, - 38,823 ft, " " " " 

11 hours per day. 

10514 ss 4 

The mill which made this cut was a machine 
having 8-ft. wheels, and with a capacity for logs 
5 feet square or 6 feet diameter. 

The next run was in Lambs' mill B, and the 
report is more in detail : 



198 



Practical Catechism. 




Practical Catechism. 199 

A third run with the same kind of machine, 
but with direct attachment, was as follows (11 
hours per day) : 
Nov. 12, - 43 Logs, scaling 25,954 ft., cutting 33,534 ft. 
" 13, - 42 " " 23,278 ft., '• 30,235 ft. 

80 per cent, went to 1-in. lumber. 

This is good work. 

SOLDERS. 

Q. How may aluminium be soldered ? 

A. "Soldering this metal in large surfaces 
has not been successfully accomplished up to 
the present. Small surfaces of the metal can be 
readily soldered by the use of pure zinc and 
Venetian turpentine. Place the solder upon 
the metal, with the Venetian turpentine, and 
heat gently with a blow-pipe until the solder is 
melted ; it will then be found to have fixed it- 
self firmly to the aluminium. The trouble with 
this, as with other solders, is that it will not 
flow on the metal. Therefore large surfaces are 
not easily soldered." 

Q. How can a good solder be made, that will 
melt below the temperature of boiling water ? 

A. One part each of tin, lead, and cadmium, 
with four of bismuth, will melt at 165 deg., but 
lose its tenacity at 155 deg. It is not very strong 
as a solder, still it will do to solder brass with. 



200 



Practical Catechism. 



Q. How may cast iron be brazed ? 

A. " Cast iron may be easily brazed, if, like 
doing other peculiar jobs, 'you know how to 
do it.' Have the iron clean ; make it free from 
grease and acids, which may be injurious ; choose 
any soft brass, or make some for this purpose. 
The yellow brass used in brazing copper will 
do ; it must contain a large percentage of zinc, 
or its melting point will be not much lower than 
that of the cast iron itself. 

Put on the borax before heating the iron. 
Dissolve the borax and apply the solution 
freely to the parts to be brazed. By doing this 
before heating a film of oxide is prevented from 
forming upon the iron. Fasten the parts to- 
gether, and heat in a clear charcoal fire. Soft 
coal is not suitable, there is too much sulphur 
in it. 

Heat the work gradually. Apply heat to the 
largest piece, and keep that piece the hottest. 
Sprinkle on powdered borax and brass filings, 
and use plenty of borax. Watch carefully, and 
get the iron up to a red heat before any of the 
brass melts. The brass will not adhere unless 
the iron is hot enough to melt the brass. 

Be very careful not to get the iron too hot, or 
away it melts and the job is lost. When the 
brass ( runs/ remove from the fire immediately, 



Practical Catechism. 201 

and wipe off the superfluous brass, cool off 
slowly, and finish up the joint." 

Am. Machinist, 

STRENGTH OF MATERIALS.* 

Q. What safe internal working pressure will 
a 2 ft. length of ordinary 12 inch wrought iron 
pipe, with an ordinary 12 inch cast iron cap on 
each end, stand ? 

A. The Edw'd Barr Co. states that it has had 
12 inch wrought iron pipe one-half inch thick 
stand 3,500 lbs. per square inch ; and that if 
the standard 12 inch pipe was fitted with cast 
iron caps, the latter properly made and the pipe 
properly welded, 1,000 lbs. per square inch 
would be a safe working pressure. The caps 
should be heavy and rounded on the corners. 

Q. What is the rule for computing the strain 
that can be safely borne by new ropes, hawsers 
and cables ? 

A. The U. S. Navy test is 4200 lbs. for a 
white rope of three strands of best Riga hemp 
of If inches in circumference ; 17,000 lbs. per 
square inch of cross section ; but 14,000 lbs. is a 
safer unit. A rule for new white ropes 2J // to 
12" circumference is to square the circumfer- 



* See also under Alloys, Beams, Calculations, etc. 



202 



Practical Catechism. 



ence and multiply by the numbers in the fol- 
lowing table : 



Inches Cir. 


3 Strand. 


4 Strand. 


2J to 6 
6 " 8 
8 " 12 


1140 
1090 
1045 


1330 
1260 

880 



To allow for chafing, deduct J from the 
strain. 

Q. How can the proper size of new white 
rope for a given strain, be determined ? 

A. Divide the strain in pounds by the con- 
stants in the preceding table, and take the 
square root of the product, for the circumference 
is inches. 

Q. How can you compute the circumference 
of a link of chain to stand a given strain ? 

A. Divide the strain in pounds by 4,000, and 
the square root of the quotient will give the 
circumference of one part of the link of chain 
in inches. Thus to carry 100,000 lbs. requires 
4/100,000^-4000= 4/25=5 inches circumfer- 
ence, corresponding to 5-7-3.1416= practically 
1.6 inches diameter. 

Q. Assuming that a girder, such as is used 
in building elevated railroads, and weighing 
about eleven net tons, is to be lifted with a sin- 



Practical Catechism. 203 

gle hook, what size and thickness of iron hook 
would be required ? 

A. Two and one-half inch round iron having 
a tensile strength of 50,000 to 60,000 lbs. per 
square inch ; the bend in the curve having a 
radius of two and one-half inches. Or, a some- 
what smaller area, of oval cross section, in the 
curved portion. 

Q. If in lifting such a heavy weight, a hook 
breaks square off without bending, would that 
indicate the quality of iron used to make the 
hook ; if so, of what quality of iron would it in- 
dicate that the hook was made ? 

A. It would show that the iron was brittle, 
and of bad quality ; perhaps " cold short " or 
containing phosphorus. 

Q. If the quality of iron used in the hook 
was good and the weight required to be lifted 
was greater than the hook could stand, should 
not the latter bend before breaking ? Would it, 
if made of good iron, break at all ? 

A. A hook should open out if not strong 
enough to carry the load. It should bend and 
tear without breaking off short. 

Q. Assuming that a hook such as described 
broke, was it not practicable and easy to dis- 
cover, before the hook was made, whether the 
iron to be used in making the hook was good or 



204 Practical Catechism. 

bad? If so, what test would be required to 
discover this ? 

A. The quality of the iron can be determined 
before making up into hooks, by two tests ; by 
nicking the bar and cutting off a piece and ob- 
serving the fracture ; and by bending it cold to 
a very short radius. The best iron will show a 
line silky fiber, lustrous without glittering ; not 
at all crystalline ; and should bend back paral- 
lel upon itself, with a very small space between 
the two sides of the bend ; or should even bend 
back flat upon itself without tearing open the 
outer side of the bend. 

Q. Assuming that girders of from seven to 
eleven net tons weight are to be lifted, what 
should be done with respect to the hooks to be 
used in this work, to secure good and substan- 
tial hooks ? 

A. The hooks should be made of refined iron 
known to be of the best quality ; should be 
made by a competent blacksmith so as not to in- 
jure their fiber in working; should be of a 
practical shape and sufficient size ; and the iron 
should be tested before making up into hooks. 
Two hooks might very well be used in order to 
lessen the probability of accident. Such pre- 
cautions are necessary to be taken because 
chains are liable to be kinked and to drop their 



Practical Catechism. 20'") 

loads a slight distance, suddenly, so that the 
load is removed from the chain and then in- 
stantly applied. Such sudden application of 
a load doubles its effectiveness in breaking a 
chain. 

Q. Does not the fact that a hook broke off at 
the bend in lifting a girder without the hook 
bending, prove absolutely that the hook was 
made of bad iron ? 

A. The breaking of a hook at the bend with- 
out opening out at all is a proof in itself that it 
was made of bad iron, entirely irrespective of its 
dimensions and proportions. 

SUGARS. 

Q. What are the classes of useful sugars 
which we use ? 

A. Grape sugars, chiefly found in fruits ; cane 
sugars, chiefly found in stems ; manna sugars, 
chiefly found in leaves; and milk or animal 
sugar. 

Q. What are the grape sugars ? 

A. They are divided into grape sugar and 
honey sugar, fruit sugar and potato, starch and 
paper sugars. 

Q. How is starch sugar made ? 

A. By treating boiled sugar with sulphuric 



206 Practical Catechism. 

acid, and then separating the acid by lime. Or 
12 or 15 lbs. of malt may be added to 100 of 
starch, the mixture heated for three hours to 
160 deg. or 170 deg. Fahr., and the syrup then 
filtered and evaporated. 

Q. How is paper sugar made ? 

A. By using paper, raw cotton, flax, cotton or 
linen rags, or sawdust, with sulphuric acid, 
water and heat. 

Q. What are the varieties of cane sugar ? 

A. Sugar-cane or Chinese' sugar, beet-root or 
European sugar; palm or date sugar ("jag- 
gery"), maple or North American sugar; maize 
or Mexican sugar, and sorghum sugar. 

temperatures. 

Q. How can temperatures expressed in one 
thermometric scale be reduced to the others ? 

A. Each degree Fahrenheit is § degree Cen- 
tigrade (Celsius), or f deg. Reaumur. The 
freezing point of water is C, K., 32 deg. 
Fahr. The boiling point of water is 100 deg. 
C, 80 deg. R., 212 deg. Fahr. Then any given 
temperature in Fahr. may be reduced to C. by 
taking 32 deg. from it and taking § the remain- 
der. Fahr. may be reduced to R. by taking 32 
deg. from it and taking f the remainder. R. 



Practical Catechism. 207 

may be reduced to C. by taking § the number 
of degrees. R. may be reduced to Fahr. by 
multiplying by § and adding 32 deg. C. may 
be reduced to Fahr. by multiplying by § and 
adding 32 deg. C. may be reduced to R. by 
multiplying by f . 

Q. What is a reliable method of measuring 
very high temperatures, as for instance that of 
a blast furnace ? 

A. By heating a mass of platinum of a known 
heat, in the flame, withdrawing it and measur- 
ing the heat units which it has absorbed. 

Q. How can a pyrometer be constructed ? 

A. You probably mean an expansion or a 
contraction pyrometer. These are as a general 
thing useless. Wedgwood used a cylinder or a 
truncated cone of vitrified clay, which contracts 
by heat, and measured the distance which when 
heated it would slide between two converging 
metallic bars. If the cones contracted regularly 
with each 1G0 deg. of heat, this would be a good 
pyrometer ; but they do not. Daniell's pyro- 
meter employs a metal bar in a blacklead 
(graphite) case. 

The best way is to heat in the flue or fire the 
temperature of which is to be measured, a plat- 
inum or other metal ball of given weight, and 
to plunge it in a known weight of water of 



208 Practical Catechism. 

known temperature, calculating from the rise in 
temperature of the water the temperature of the 
metal before cooling. If platinum be taken, 
and the water is double the weight of the plat- 
inum, as that metal has a speeific heat or capac- 
ity for heat of .0314 compared with water as 
unity, the rise in temperature of the platinum 
for a given amount of heat will be to that of the 
water as 2 is to .0314 or as 63.7 to 1. Then the 
temperature of the platinum before cooling will 
be equal to that of the water before heating, 
plus 63.7 times the rise in temperature of the 
water. Thus if 1 ounce of platinum heat 2 
ounces of water from 60 deg. to 100 deg. Fahr., 
the platinum has a temperature of 60-f-(40x 
63.7) =60+2548=2608 deg. If it heats 4 ounces 
of water from 60 deg. to 80, it will have a tem- 
perature of 60+(20xl27.4)=2608 again. If 
it be tried with two different weights of water 
and give the same result there will have been 
no error. But it is almost impossible so to en- 
velop in non-conductors the vessel containing 
the water, that there will be no radiation ; hence 
the reading is always apt to be a trifle too low. 
It can never be too high if the weights and tem- 
peratures be taken correctly, and there is no 
error in figuring. 



Practical Catechism. 209 

Q. What are the liquefaction temperatures of 
various gases ? 

A. The temperature at which the common 
gases become liquefied are given as follows by 
Prof. Dewar, the numbers expressing degrees 
below zero Fahrenheit: Carbonic acid, 112 deg. ; 
nitrous oxide, 130 deg. ; ethylene, the chief illu- 
minating constituent of common coal gas, 154J 
deg. ; oxygen, 299 deg. ; nitrogen, 232 deg. ; 
air, 314 deg. ; carbonic oxide, 215J deg. The 
greatest cold yet produced by man, 328 deg. be- 
low zero, was obtained by two Russian physi- 
cists by the use of liquid oxygen. 

Q. How can intense cold be produced by 
merely dissolving chemicals in water ? 

A. Not very readily. A moderate degree of 
cold can be produced by dissolving certain salts 
in water, and lower temperature by mixtures of 
certain salts and acids, and more intense de- 
grees with snow or ice and chemicals. The 
following table shows the fall of temperature 
produced by proportional mixtures of salts and 
acids with water alone : — 



210 



Practical Catechism. 



COLD-PRODUCING MIXTURES. 



No 



Mixtures. 



Fall of 
Temperature. 



10 



11 



Nitrate of Ammonia.. 1 

Water 1 

Muriate of Ammonia. . 5 

Nitrate of Potash 5 

Water 16 

Muriate of Ammonia. . 5 

Nitrate of Potash 5 

Sulphate of Soda 8 

Water 16 

Sulphate of Soda 3 

Diluted Nitric Acid... 2 
Nitrate of Ammonia. . . 1 
Carbonate of Soda.. .. . 1 

Water 1 

Phosphate of Soda 9 

Diluted Nitric Acid. . . 4 

Sulphate of Soda 8 

Hydrochloric Acid 5 

Sulphate of Soda. ..... 5 

Dilute Sulphuric Acid. 4 

Sulphate of Soda 6 

Muriate of Ammonia.. 4 

Nitrate of Potash 2 

Dilute Nitric Acid.... 4 

Sulphate of Soda 6 

Nitrate of Ammonia. . 5 

Dilute Nitric Acid 4 

Phosphate of Soda 9 

Nitrate of Ammonia. . 6 
Dilute Nitric Acid 4 



Fahr. 
from-f 50° to-f4° 

from-j-50° to-f 10° 



from-f 50° to-f 4° 

from+50° to— 3° 

from-f 50° to— 7° 

from-f 50° to— 12° 
from-j-50° to— 0° 
from+50° to-f 3° 

from-f 50° to— 10° 

from-f 50° to— 14° 
from+50° to— 21° 



F. 

46° 

40° 

46° 

53° 

57° 

62° 
50° 

47° 

G0° 

G4° 
71° 



Practical Catechism. 



211 



THE FOLLOWING TABLE GIVES PROPORTIONAL 

MIXTURES OF SALTS AND ACIDS 

WITH SNOW OR ICE. 



No 


Mixtures. 


Fall of 
Temperature. 




12 
13 

14 

IS 

16 

17 
18 
IS 

20 


Muriate of Soda (com- ^ 

mon salt) 1 V 

• Snow, or pounded ice. . 2 j 

Muriate of Soda 2] 

Muriate of Ammonia. . 1 > 
Snow, or pounded ice.. 5) 

Muriate of Soda 10 1 

Muriate of Ammonia. . 5! 

Nitrate of Potash 5 [ 

Snow, or pounded ice.. 24 J 

Muriate of Soda 5} 

Nitrate of Ammonia. . . 5 > 
Snow, or pounded ice.. 12 J 
Dilute Sulphuric Acid. 2 ) 

Snow 3 f 

Muriatic Acid 5 \ 

Snow 8 J 

Dilute Nitric Acid 4 ) 

Snow 7 j 

Muriate of Lime 5 ) 

Snow 4 j 

Crystallized Muriate of i 
Lime 3 > 


Fahr. 

from any temp. 

to— 5° 

from any temp, 
to— 12° 

from any temp, 
to— 18° 

from any temp, 
to— 25° 

from-f 32° to— 23° 

from-f-32° to— 27° 

from+32° to— 30° 

from+32° to— 40° 

from+32° to— 50° 

from+32° to— 51° 


F. 

55° 
59° 
62° 
72° 

8?° 


21 


Snow 2J 

Potash 4) 

Snow 3j 


83° 



212 



Practical Catechism. 



The following table gives mixtures partly selected from those 
preceeding, and so combined as to increase or extend 
the cold to the greatest extreme: — 



No 



Mixtures. 



Fall of 
Temperature. 



o 

C3 



22 

23 
24 

25 

26 
27 

28 
29 
30 
31 
32 

33 

34 



Sea Salt 51 

Muriate of Ammonia) K ! 
Nitrate of Potash.... j ° f 
Snow, or pounded ice., lj 

Sea Salt 5" 

Nitrate of Ammonia.. . 5 
Snow, or pounded ice.. 12 

Phosphate of Soda 5 

Nitrate of Ammonia... 3 

Dilute Nitric Acid 4 

Phosphate of Soda 3 

Nitrate of Ammonia. . . 2 
Dilute Mixed acids. ... 4 

Snow 3 

Dilute Nitric Acid 2 

Snow 8 

Dilute Sulphuric Acid. 3 

Dilute Nitric Acid 3 

Snow 1 

Dilute Sulphuric Acid. 1 

Snow 3 

Muriate of Lime 4 

Snow 3 

Muriate of Lime 4 

Snow 2 

Muriate of Lime 3 

Snow 1 

Crystallized Muriate of 

Lime 2 

Snow 1 

Crystallized Muriate of 

Lime 3 

Snow. 81 

Dilute Sulphuric Acid. 10 J 



Fahr. 
from— 5° to— 18° 

from— 18° to— 25° 

from 0° to— 34° 

from— 34° to— 50° 

from 0° to— 46° 

from— 10° to— 56° 

from— 10° to— 60° 
from+20° to— 48° 
from-f 10° to— 54° 
from— 15° to— 68° 

from 0° to— 66° 

from— 40° to— 73° 

from— 68° to— 91° 



F. 

13° 

7° 

34° 

16° 
46° 

4G° 

50° 
68° 
64° 
53° 

66° 

33° 

23° 



Practical Catechism. 213 

timber and trees. 

Q. What are the general rules for the selec- 
tion of timber ? 

A. Professor Kankine says : There are certain 
appearances which are characteristic of strong 
and durable timber, to what class soever it be- 
longs. 1. In the same species of timber that 
specimen will in general be the strongest and 
the most durable which has grown the slowest, 
as shown by the narrowness of the annual 
rings. 2. The cellular tissue, as seen in the 
medullary rays (when visible), should he hard 
and compact. 3. The vascular or fibrous tissue 
should adhere firmly together and should show 
no wooliness at a freshly cut surface, nor should 
it clog the teeth of the saw with loose fibers. 
4. If the wood is colored, darkness of color is in 
general a sign of strength and durability. 5. 
The freshly-cut surface of the wood should be 
firm and shining and should have somewhat of 
a translucent appearance. A dull, chalky ap- 
pearance is a sign of bad timber. 6. In wood 
of a given species the heaviest specimens are in 
general the stronger and the more lasting. 7. 
Among resinous woods, those which have least 
resin in their pores. 

Q. What is the strongest American wood and 
what is the most elastic ? 



214 Practical Catechism. 

A. The strongest wood in the United States 
is the nutmeg hickory of Arkansas. The most 
elastic is the tamarack. The highest specific 
gravity, upon which in general depends value as 
fuel, is attained by the bule wood of Texas. 

Q. What is meant by " leaf wood ? " 

A. All trees which do not belong to the cone- 
bearing order (which embraces the pine, larch, 
fir, cypress, and cedar, etc.,) are said to be leaf 
wood. 

Q. Do endogenous trees such as those of the 
palm tribe furnish timber ? 

A. No ; they are not firm enough. 

Q. When is the heart wood of a tree at its 
greatest strength ? 

A. At the maturity of the tree ; say 100 years 
for oak, pine, ash and elm. Oak should not be 
cut before 60 years old, pine before 70, ash and 
elm before 50. 

Q. What is the best time of year for felling 
trees to get the best timber ? 

A. Either mid-winter or mid-summer. 

Q. What is the advantage of cutting in July 
or August ? 

A. The sound trees can be told from the un- 
sound by their being uniformly green while the 
others show irregular in color, etc. 



Practical Catechism. 215 

Q. Should trees be deprived of their bark at 
once after felling or not ? 

A. Yes ; it is better yet to bark them before 
felling; say in spring if they are to be cut in 
fall or winter. 

Q. Should timber be squared as soon as felled 
or let remain ? 

A. It should be squared at once ; large logs 
should be halved and very large ones quartered 
and then piled to season. 

Q. What is the length of time allowed for 
steaming timber for bending ? 

A. An hour for each inch of thickness. 

Q. What is the time required for hot air sea- 
soning ? 

A. A week per inch of thickness. 

Q. Is smoke seasoning desirable ? 

A. It not only seasons well but aids in pre- 
serving the wood. 

Q. How is oil seasoning done and for what 
purposes ? 

A. By boiling in oil ; hickory is thus treated 
for making cogs of mortise gear wheels. The 
temperature should not exceed 250 deg. Fahr., 
and the blocks should be as nearly as possible 
to the finishing size. 

Q. What is the advantage of building up 
large beams of comparatively thin pieces ? 



216 Practical Catechism. 

A. To secure uniformity of seasoning and to 
save time in seasoning. 

Q. Why does wood warp in seasoning ? 

A. Because those parts furthest from the 
heart shrink the most. 

Q. What is meant by soft wood ? 

A. That of all trees that bear cones, and some 
few others, as the white beech. 

Q. What is meant by hard wood ? 

A. The wood of all trees except the cone 
bearers, and a few exceptions such as white 
birch. 

Q. When should timber be inspected, in order 
to bring out its defects ? 

A. In dry weather. 

Q. What indicates dry rot in timber ? 

A. Yellow stains. 

Q. Is the sap wood always poorer than the 
heart ? 

A. No ; in ash, lance-wood and hickory it is 
sometimes better than the heart. 

Q. What is the effect of lime upon timber ? 

A. It hastens the rotting of damp timber; 
retards it if dry. 

Q. What kinds of wood are not attacked by 
the teredo and the limnoria ? 

A. East Indian teak, not at all, and our own 
live oak, very little. 



Practical Catechism. 217 

Q. What is meant by leaf-woods ? 

A. The wood of trees which bear flat leaves, 
as distinguished from the pines, which bear 
needle-like leaves. 

Q. When should yellow pine (spruce pine, 
short leaved pine) be cut ? 

A. In summer. 

Q. How can you tell good pine wood ? 

A. It should have a close grain, and slow 
growth as indicated by thin rings. The rings 
should not be over one-tenth inch thick ; and it 
should be round. It should smell well of resin ; 
have clear yellow and red colors and uniform 
texture; should split straight but not easily; 
not be woolly under the saw, and the shavings 
and chips should be strong and elastic. The 
shavings should be capable of being twisted 
around the fingers without breaking. 

Q. What are the faults of live-oak ? 

A. It will not receive spikes without split- 
ting ; and if exposed long in the open air in the 
rays of the sun or to winter winds it checks 
badly. 

Q. What are the faults of white oak ? 

A. It shrinks, warps and cracks in seasoning, 
hence is of very little use for boards. 

Q. How may true San Domingo (Spanish) 
mahogany be told from Honduras ? 



218 Practical Catechism. 

A. By having its pores filled with a white 
substance which is not in the Honduras, or 
"baywood." It is harder, of closer grain, 
darker in color and stronger than the bay wood. 

Q. How should lignum vitae sheaves be 
turned ? 

A. With the heart in the center, and a ring 
of sap wood about the rim. This will greatly 
lessen the liability to crack. 

Q. What disadvantage of oak in building ? 

A. Its acid sap destroys iron nails and spikes. 

Q. How much is gained in strength by oil 
seasoning timber ? 

A. From 15 to 20 per cent. 

Q. What is the proportion of strength with 
and across the grain in the various woods ? 

A. For pines and spruce the tenacity is from 
one-tenth to one-twentieth across the grain 
what it is with it ; harder woods from one-sixth 
to one-fourth. 

Q. How about the strength of timber as es- 
timated by published tables of strength ? 

A. For very large timber about 25 to 30 per 
cent, should be deducted. 

Q. How about the compressive strength of 
dry wood as compared with wet ? 

A. Wet wood has been found to be only 
one-half as strong as dry, to resist compression. 



Practical Catechism. 219 

Q. What is the strength of a flat-ended 
wooden pillar as compared with one having 
round ends ? 

A. If of considerable length in proportion to 
their diameter, the flat end ones are about 3 
times as stroug as those with round ends. 

Q. What are the qualities desired in wood 
for pattern making ? 

A. It should be light, should not check, 
should be easily worked. 

Q. What are the most elastic woods ? 

A. Ash, hickory, hazel, lancewood, small 
chestnut, yew, snake-wood. 

Q. What are woods which are both elastic 
and tough ? 

A. Oak, beech, elm, lignum vitae, walnut, 
hornbeam. 

Q. What woods have even grain, suitable 
for engraving ? 

A. Pear, pine, box, lime. 

Q. What woods are desirable in dry works ? 

A. Cedar, oak, poplar, yellow pine, chestnut. 

Q. What are durable for wet constructions, 
such as piles, foundations, flumes, etc. ? 

A. Elm, alder, beech, oak, plane, white cedar. 

Q. What woods are good for ship building ? 

A. Cedar, pine (deals) firs, larches, elms, 
oak, locust, teak. 



220 Practical Catechism. 

Q. What are desirable in house building ? 

A. Pine, oak, white wood, chestnut, ash, 
spruce, sycamore. 

Q. What are desirable for making furniture ? 

A. For common, beech, birch, cedar, cherry, 
pine, white wood. For best, amboyna, black 
ebony, mahogany, cherry, maple, walnut, oak, 
rose-wood, satin-wood, sandal wood, chestnut, 
cedar, tulip wood, zebra-wood, ebony. 

Q. What woods are used for machinery and 
mill work ? 

A. For frames, ash, beech, birch, pine, elm, 
and oak. For rollers, etc., box, lignum vitae, 
mahogany. For cogs, crab, hornbeam, locust, 
hickory, maple. For foundry patterns, alder, 
pine, cherry, mahogany. 

Q. Are there any fancy woods the colors of 
which either fade or darken by age ? 

A. Tulip wood will fade by light ; all the 
rest darken and mellow by age. 

Q. What sort of varnishes should be laid 
over fancy woods ? 

A. Only the whitest. 

VENTILATION. 

Q. How much carbonic acid per hour will an 

average man exhale under ordinary conditions ? 

A. From lungs and body 0.6 to 0.7 cubic feet 



Practical Catechism. 221 

— about the same as that from a lighted oil 
lamp or from two candles. 

Q. What is the allowable pollution of the air 
by carbonic acid ? 

A. About 6 volumes in 10,000 ; the normal 
proportion being 4 volumes in 10,000 or four- 
hundredths of one per cent. 

Q. How much air does an adult require per 
hour for breathing ? 

A. Depends upon the kind. An adult con- 
sumes about 350 cubic feet in 24 hours, and the 
rule for living apartments is 700 cubic feet of 
space per person. There is no use in having 
700 cubic feet, or twice that, if it is never 
changed, or if it is merely changed from one 
lot of bad air to another. 

Q. How much air is needed per head per 
hour, for ventilation ? 

A. Hood found 3 J to 5 cubic feet per minute or 
210 to 300 cubic feet per hour, per head, enough 
in winter, and 5 to 10 cubic feet per minute or 
300 to 600 cubic feet per hour, in winter. This 
rate kept the air " pure and wholesome." 

Q. Is there any rule by which to calculate the 
amount of air discharged through a ventilator, 
per square foot of opening, when the differences 
of temperature and the height of the opening 
above the floor, are given ? 



222 



Practical Catechism. 



A. The following table (by Hood) will give 
it without calculation. It gives about three- 
fourths the quantities calculated for pure air in 
the room, etc., to allow for carbonic acid, fric- 
tional resistance, resistance of angular devia- 
tions, etc. : 



AIR DISCHARGED THROUGH VENTILATOR PER 

SQUARE FOOT OF OPENING FOR VARIOUS 

HEIGHTS AND DIFFERENCES OF 

TEMPERATURE. 



Height of 

Ventilator 

from 


Excess of Temperature of the Room above 

that of the External Air, in 

Fahrenheit Degrees. 


Floor. 


5° 


10° 


15° 


20° 


25° 


30° 


Feet. 


cu. ft. 


cu. ft. 


cu. ft. 


cu. ft. 


cu. ft. 


cu. ft. 


10 


116 


164 


200 


235 


260 


284 


15 


142 


202 


245 


284 


318 


348 


20 


164 


232 


285 


330 


368 


404 


25 


184 


260 


318 


368 


410 


450 


30 


201 


284 


347 


403 


450 


493 


35 


218 


306 


376 


436 


486 


531 


40 


235 


329 


403 


465 


518 


570 


45 


248 


348 


427 


493 


551 


605 


50 


260 


367 


450 


518 


579 


635 



Q. What is the best method of arranging 
steam pipes in a vertical flue for ventilating 
purposes ? 



Practical Catechism. 223 

A. To run the pipes vertically in the flue for 
a distance of five to twelve feet at its base ; sep- 
arating them by sheet iron partitions which 
receive heat from the pipes by direct radiation 
and give it out to the air. By this means with 
18 two-inch pipes, twelve feet long, an exterior 
surface of steam pipes of 108 square feet gives 
an actual efficient surface for heating the air of 
680 square feet. 

Q. What is the rule for getting the ascension 
of air in mine shafts, by difference of tempera- 
ture ? Something that has been proved by act- 
ual practice is desired. 

A. Hawksley, in the Proceedings of the Institu- 
tions of Civil Engineers, vol. XXX, states that the 
formula given in vol. VI tallies exactly with the 
results of Mr. Xicholas Wood's experiments on 
the ventilation of collieries. This formula, re- 
duced to a rule for those who do not under- 
stand algebra, calls for a calculation as fol- 
lows: — 

Multiply the difference in temperature be- 
tween the upcast and the downcast shaft (in 
degrees Fahrenheit) by the depth of the shaft 
(in feet) and by the section of the air course (in 
square feet) ; divide it by the temperature in 
the upcast, plus 448. Call this quotient num- 
ber one. Multiply the periphery of the air- 






224 Peactical Catechism. 

course (in feet) by the length traversed by the 
current (in feet) ; add to this product 368 times 
the section of the air course (in square feet). 
Divide quotient number one by the sum just ob- 
tained, and take the square root of the product. 
The result will be the velocity of the current, in 
feet per second. 

Q. What is the rule for the flow of air in 
pipes and other conduits ? 

A. In pipes, where the velocity is given or 
required in feet per second, the head in feet of 
air, the diameter and the length in feet, the rule 
(here given for the first time in book form, and 
deduced from Hawksley's formula) is that the 
velocity is got by multiplying the head by the 
diameter, and dividing by the length, then tak- 
ing the square root of the quotient, and multi- 
plying by 48. 

Where the head is given in inches of water, 
then, taking the density of water as 815 times 
that of air, the velocity is got as before, using 
396 as a multiplier instead of 48. The head 
will be got by multiplying the length by the 
square of the velocity and dividing by 156,800 
times the diameter. 

The foregoing are for pipes only. For con- 
duits of irregular forms, as shafts and airways 
in mines and tunnels, the perimeter and the 



Practical Catechism. 225 

sectional area must be considered. Then the 
velocity is got by multiplying the sectional area 
(in square feet) by the head (in inches of water) 
and dividing by the perimeter (in feet) and by 
the length (in feet) ; taking the square root, 
and multiplying by 796. 

The head in inches of water will be got by 
multiplying the square of the velocity (in 
feet per second) by the perimeter (in feet) and 
by the length (in feet) ; and dividing by 633,000 
times the sectional area in square feet. 

The quantity of air discharged from a pipe 
(in cubic feet per second) is equal to the pro- 
duct of the velocity by the sectional area ; hence 
will be obtained, for a pipe, by multiplying the 
head (in inches of water) by the fifth power of 
the diameter (in feet) ; dividing by the length 
(in feet) ; taking the square root of the quotient, 
and multiplying by 311. 

For a passage of any form of section the cubic 
feet of air discharged per second will be got by 
multiplying the cube of the area (in square feet) 
by the head (in inches of water) ; dividing by the 
perimeter (in feet) and by the length (in feet) ; 
taking the square root, and multiplying by 796. 

Q. How can the effective horse-power ex- 
pended on the net work done in drawing air 
through a pipe or passage, be found ? 



226 



Practical Catechism. 



A. By multiplying the product of the sec- 
tional area by the velocity in feet per second, 
and by the head or " drag " in pounds per 
square foot, divided by 550. 

Q. How much pressure per square foot is an 
inch head of water equal to ? 

A. 5.2 lbs. per square foot. 

Q. With a difference of one-tenth of an inch 
of mercury as indicated by the barometer be- 
tween a downcast and an upcast shaft, what 
would be the pressure per foot and what would 
be the motive column, the temperature of the 
down-cast averaging 62 deg. ? 

A. A tenth of an inch of mercury at 32 deg. 
Fahr. is equal to a head of 13.6 inches of water, 
at 32 deg. Fahr., or to 93.12 feet of air, of uni- 
form density, at 32 deg. Fahr., or to 7.0922 lbs. 
per square foot. At 62 deg. Fahr., a column of 
mercury .01417 inch high gives a pressure of 
1 lb. per square foot ; and at 32 deg. Fahr., 
.0141 inch gives the same pressure. Therefore 
the figures for 32 deg. need to be multiplied by 
.0141 and divided by .01417 to give the results 
for 62 deg. Fahr. 

Q. If there are two airways in a mine, one 5 
feet by 8 feet and the other 5 feet by 6 feet, with 
equal volumes of air passing through each ; if 






Practical Catechism. 227 

the airway 5 feet by 8 feet is 1000 feet long, 
what is the length of the other ? 

A. The lengths of such conduits are found by 
multiplying 633,616 by the cube of the area and 
by the head, and dividing by the square of the 
quantity of air delivered, and by the perimeter 
of the conduit. Then they will be in the pro- 
portion of the cubes of the areas, times the 
head, divided by the perimeters ; or as f f times 
the one head is to f J times the other head. 
But as the heads are unequal in the two shafts 
" the example cannot be done " directly. As- 
suming the airways to be horizontal and that 
the smaller one has a length proportional to its 
area, that is, 750 feet, and that the quantity of 
air is 1000 cubic feet per second, the head in 
the longer and larger shaft is (1,000,000 X 26 X 
1000) - (633,616 X 40X40X40) =26,000,000,000 
-5-40,551,424,000=0.6411 inches of water. The 
smaller and shorter one would have a head of 
(1,000,000 X 22 X 750) -- 633,616 X 30 X 30 X 30) = 
16,500,000,000-5-10,771,472,000=1.53 inches. 

Assuming the smaller one to be only 400 feet 
long, it would have a head of 1.53 X. 4= 0.612 
inches. 

Working the thing the other way about, to 
get the quantity with the other data given, we 
have the small tunnel delivering, with 0.612 



228 Practical Catechism. 

inch head, 796 times the square root of the quo- 
tient got by dividing the head times the cube of 
the area by the product of the periphery by the 
length, or 796 times the square root of (27,000 
X.612)-f-(22x400)=796 times the square root 
of 1,8777=796X1.373=1092.9 cubic feet. 

WATERS. 

Q. What makes some river water red? 

A. Bed marl through which it flows. 

Q. What makes it milky in Iceland and the 
Andes ? 

A. White earth which it holds in suspension. 

Q. What makes it brown ? 

A. Flowing through boggy lakes or running 
through a peaty country. 

Q. What makes it black ? 

A. It is so when the quantity of vegetable 
matter is excessive, as in the Kio Negro of 
South America. 

Q. Where is it green and why ? 

A. In the Geysers of Iceland, in the Swiss 
lakes, among the islands of the South Sea, and 
around the British Islands, because of the yel- 
low matter which it holds in suspension or so- 
lution. 

Q. What is the natural color of water and 
where may it be seen ? 



Practical Catechism. 229 

A. Blue; in clear and deep waters such as 
those of the Bay of Naples, in parts of the Pa- 
cific, and in the Grotto of Capri. 

Q. What class of soil gives the purest water ? 

A. Granite. About the purest natural water 
is that of the river Loka in the north of 
Sweden. This contains only about 1-20 of a 
grain of solid mineral matter to the imperial 
British gallon. 

Q. How are hard waters generally made 
softer ? 

A. By boiling. 

Q. Suppose they contain gypsum (plaster of 
Paris ; sulphate of lime) will boiling soften it ? 

A. No ; it will require some soda to be added 
during the boiling. 

Q. What is a better and cheaper way of soft- 
ening hard water than boiling ? 

A. Adding lime water to take away that ex- 
cess of carbonic acid which held in solution the 
carbonate of lime present in the water. 

Q. W T hat will purify well water which con- 
tains organic matter ? 

A. Boiling will generally coagulate the or- 
ganic matter ; the same thing will be caused by 
filtering it through charcoal ; or by putting in 
it chips of oak wood. All these processes coag- 
ulate the albumen. Alum will do the same 



230 Practical Catechism. 

thing. In India travellers rub on the sides of 
the water jars the powder of the nuts of the 
Strychnos potatorum ; and in Egypt, the muddy 
water of the Nile is clarified by rubbing bitter 
almonds on the sides of the water vessel. 

In the 15th chapter of Exodus we read as 
follows : — " So Moses brought Israel from the 
Red Sea and they went out into the wilderness 
of Shur ; and they went three days in the wild- 
erness, and found no water. And when they 
came to Marah, they could not drink of the 
waters of Marah, for they were bitter ; there- 
fore the name of it was called Marah. And the 
people murmured against Moses, saying what 
shall we drink ? And he cried unto the Lord, 
and the Lord showed him a tree which when he 
had cast into the waters, the waters were made 
sweet." 

WEIGHTS. 

Q. Give the weights and volumes of ice and 
snow under various stated conditions ? 

A. One cubic foot of ice at 32 deg. Fahr. 
weighs 57.50 lbs. 

1 lb. of ice at 32 deg. Fahr. has a volume of 
.0174 cubic foot, or 30.067 cubic inches. 

The volume of water at 32 deg. Fahr. is to 
that of ice at 32 deg. Fahr., as 1.000 to 1.0855 ; 
the expansion in passing into the solid state 






Practical Catechism. 



231 



being above 8J per cent, of the volume of 
water. 

The specific density of ice is 0.922, that of 
water at 62 deg. Fahr. being=l. 

The melting point of ice is 32 deg. Fahr. or 
deg. C, under the ordinary atmospheric pres- 
sure of 14.7 lbs. per square inch. Under 
greater pressure the melting point is lower, 
being at the rate of .0133 deg. Fahr. for each 
additional atmosphere of pressure. 

The specific heat of ice is .504, that of water 
beings 1. 

One cubic foot of fresh snow weighs 5.20 lbs. 
Snow has 12 times the bulk of water, and its 
specific gravity is .0833. 

WEIGHTS OF IRON AND STEEL. 

Q. What are the rules for finding the weights 
of wrought iron, cast iron, or steel, when the 
volume is given in cubic feet ? 

A. Multiply the volume by the multipliers, 
or divide by the divisors, given below : — 





Multipliers. 


Multipliers. 




Gross. 


Net. 


Gross. Net. 


Wrought Iron. 

Cast Iron 

Steel 


4.29 
4.02 
4.37 


4.8 
4.5 

4.89 


.2331 

.2488 
.2288 


.2083 
.2222 
.2045 



232 



Practical Catechism. 



The results will be in hundredweights, gross 
or net, according to which constants were used. 

Q. What are the rules for finding the weights 
of iron and steel when the volume is given in 
cubic inches ? 

A. Multiply or divide by the constants here 
given, for results in pounds : — 



Wrought Iron. 

Cast Iron 

Steel 




Divisors. 



3.597 
3.846 
3.534 






Thus 291.357 cubic inches of wrought iron 
will weigh 291.357 X. 0278=81 lbs.; or the same 
result may be got thus :— 291.357-8-3.597=81. 

Q. How do you figure the weight of castings 
from that of a white pine pattern ? 

A. Multiply the pattern weight by 14 for 
iron or tin, 15 for brass, 22 for lead, or 13.5 for 
zinc. 

Q. How do you allow for cylindrical core or 
prints ? 

A. Multiply the square of core or print 
diameter by its length in inches and by 0.0175, 
to get the weight of core or print to be taken 
from that of the pattern. 

Q. A pine pattern plunged in a vessel of 









Practical Catechism. 233 

water, makes 114 cubic inches overflow. What 
would be the weight of the casting made from 
the pattern ? 

A. 114X.26 equals 29.64 lbs. 

Q. There being no scales handy, a wrought 
iron forging was plunged in a hogshead full of 
water, and it made 397 cubic inches of water 
overflow. What was the weight of the forg- 
ing? 

A. 397 X. 278 equals 110.366 lbs. 

Q. How can fraudulent balances be detected, 
when the weights are true ? 

A. Weigh a given quantity of some article, 
and then transpose weight and article. If the 
article weighed is lighter than the weight, the 
weight will preponderate; and contrariwise if 
the article is overweight. 

Q. How can you weigh out a given quantity 
correctly on false balances ? 

A. Put a true weight in one pan and bal- 
ance it with shot ; then remove the weight and 
balance the shot with the material to be 
weighed. 

Q. How can you find the weight of a log, bar, 
or beam, by balancing it and using a known 
weight as a counterpoise ? 

A. Balance it on a fulcrum ; note the distance 
between the fulcrum and the end of the longest 



234 Practical Catechism. 

arm. Hang the known weight from the long 
arm and shift the fulcrum until the whole bal- 
ances again. Subtract the distance between the 
two fulcrum positions from the original length 
of the long arm ; multiply the remainder by the 
weight, divide the product by the distance be- 
tween fulcrum positions, and the greatest will 
be the weight. 

Thus : — a tapered timber 20 feet long balances 
at 12 feet from the less end, but when a 160 lb. 
man stands at the extremity of the long end, 
it balances at 10 J feet from the less end ; then 
12— 1GJ=1|; 12— 1J=10J; 10JXl60=1680 
lbs. 

Another 20 foot tapered piece balances at 14 
and 13 feet respectively with the same man ; 
then 14-13=1; 13—1=12; 12x160=1920 
lbs. 

Q. " What is the difference or the correspond- 
ence between degrees Baume and specific grav- 
ity, expressed decimally, as compared with 
water?" 

A. There are two Baume scales — one for 
liquids lighter than water and the other for 
those heavier. In the one intended for oils 
and other liquids lighter than water, water itself 
is considered at 10 deg. ; this of course corre- 
sponding to a specific gravity of 1.00. There is 



Practical Catechism. 235 

no other point of equivalence of even degrees, 
specific gravity of 0.700 being nearly 69 deg. B. 
60 deg. B. comes about 0.7338 ; 50 deg. B., about 
0.7551; 40 deg. B, about 0.823; 30 deg. B, 
about 0.874 ; 20 deg. B., about 0.9654. 

On the other scale, for liquids heavier than 
water, water itself is taken at zero or deg. ; 
this of course corresponding to specific gravity 
1.000. 10 deg. B. of this scale is about 1.06 ; 
20 deg. B., 1.11; 30 deg. B., practically 1.26; 
40 deg. B., about 1.38 ; 50 deg. B., 1.63 ; 60 deg. 
B., 1.715 ; 70 deg. B., 1.945 ; while 72 deg. B. 
corresponds to specific gravity of 2.000 or 
double that of water. 

Thus we see that on one scale water is 10 
deg. B. and on the other it is deg. B. 

WINES, BEERS, ETC 

Q. What is the order of acidity of wines ? 

A. Moselle, Khine, Burgundy, Madeira, 
"Claret" (so called) Champagne, Port and 
Sherry. 

B. What is the percentage of alcohol in vari- 
ous wines and liquors ? 

A. Brandt gives the following . 



236 



Pbactical Catechism. 






Small Beer....l. and 1.08 

Cider 5.2 " * 9.8 

Porter 3.5 " 5.26 

Brown Stout... 5.5 " 6.8 

Ale 6.87" 10. 

Perry 7.26 

Bhenish 7.58 

Moselle 8.7 

Johannisberger 8.71 

Elder Wine 8.79 

Claret ordinaire 8.99 

Tokay 9.33 

Rudesheimer. 10.72 

Marcobrunner 11.6 

Gooseberry Wine 11.84 

Fontignac 12.89 

Hochheimer 12.03 

Vin de Grave 12.08 

Champagne 12.61 

Champagne (Burgun- 
dy) 14.57 

Hermitage (red) 12.32 

Hermitage (white). ..17.43 

Amontillado 12.63 

Barsac 13.86 

Sauterne 14.22 



Port (white) 15. 

Bordeaux 15.1 

Shiraz 15.52 

Malmsey 16.4 

Sherry.. 17.17 

Sherry (old) 23.86 

Alba Flora 17.26 

Constantin (red) 18.92 

Port 23. 

Colares 19.75 

Lisbon 18.94 

Malaga 17.2 

Cape Muscat 18.25 

Teneriffe 19.79 

Lachryma 19.7 

Currant Wine 20.55 

Madeira 22.27 

Madeira (Sercial) 27.4 

Marsala 25.09 

BaisinWine 25.12 

Cape Madeira 29.51 

Gin 51.6 

Brandy 53.39 

Bum 53.68 

Irish Whiskey 53.9 

Scotch Whiskey 54.32 



Q. What are the principal distinctions be- 
tween wines and beers ? 

A. They contain but little solid nutritious 
matter ; are free from bitter or narcotic ingre- 
dients ; are all fermented without the addition 
of yeast or other outside ferment ; and contain 



Practical Catechism. 237 

other acids besides the vinegar to which sour 
beer owes nearly all its acidity. 

Q. What causes the vinous odor of wine ? 

A. A minute portion of an ethereal sub- 
stance, to which the name of cenanthic ether is 
given. Few wines contain more than 1-40,000 
part of it. 

Q. To what is the bouquet of wines due ? 

A. To various ethers in even more minute 
quantity than the cenanthic ether. The recep- 
tacle in which they are contained also influences 
the flavor ; thus casks made of the wood of the 
white mulberry give a slight bouquet resem- 
bling violets to sherry that has been long kept 
in them. 

Q. What is the principal economy in making 
grain whiskey ? 

A. Adding unmalted grain or even potato 
starch to the malted grain ; the diastase or fer- 
ment of the malted grain will convert into 
sugar ten times as much starch as is contained 
in the malted grain. Thus the distiller saves 
both the expense of malting his grain, and the 
loss (about eight per cent.) in the malting pro- 
cess. He is also able to use cheaper materials. 

Q. What is the main flavoring matter in po- 
tato brandy ? 

A. An oily liquid closely related to wine 



238 Pbactical Catechism. 

alcohol, and known as amyl alcohol ; it is the 
chief ingredient of fusel oil. 

Q. How may amyl, butyl or propyl alcohols 
be detected in spirit ? 

A. Koughly, by pouring a little of the sus- 
pected gin or whiskey on the hands, rubbing 
them together, and letting the more volatile 
wine alcohol evaporate. A pungent, suffocat- 
ing, and noxious odor remains on the skin, 
showing fusel oil or one of the three "higher" 
alcohols of amyl, butyl or propyl. 

Q. How much beer, or how much whiskey 
may be made from a bushel of malt ? 

A. In average year, two gallons of proof 
spirit or eighteen gallons of light ale or porter. 

Q. What is the proportion of ash taken by 
tobacco from the soil ? 

A. One hundred lbs. of dried tobacco leaf 
yields from eleven to twenty-eight lbs. of ash ; 
thus placing this plant among the most exhaust- 
ing of crops. 

Q. What is the difference between spirits and 
ethers ? 

A. If spirits of wine (alcohol) is mixed with 
twice its bulk of sulphuric acid and distilled by 
heat, there passes over a light, volatile and fra- 
grant liquid known as wine ether, or ordinarily, 
" ether." Chemically speaking, it is the oxide 






Practical Catechism. 239 

of ethyl, while alcohol is the hydrate of ethyl. 
Wood spirit is methyl alcohol, wood ether is 
methyl ether. Potato spirit is amyl alcohol ; 
potato ether is amyl oxide. 

WORK.* 

Q. Is there any set standard, in law or in 
mechanics, as to what constitutes a day's work 
for a laborer ? 

A. None that has been legally fixed or which 
has received the sanction of common law. But 
contractors of course have a fairly definite idea 
as to how much work the average laborer is 
capable of ; and the following (on the authority 
of Trautwine) may be taken as a fairly good 
guide : 

A practised laborer hauling along a level 
road by a rope over his shoulders ; or in a cir- 
cular path, pushing before him a horizontal 
lever, at a speed of from 1 J to 3 miles per hour, 
exerts about £ lb. part as much force as a horse ; 
or 2,200,000 ft. lbs. per day ; or 3666f ft. lbs. 
per minute of a day of 10 hours of actual 
hauling or pushing. 

But laborers frequently have to work under 
circumstances less advantageous for the exer- 



*See also under Power. 



240 Practical Catechism. 

tion of their force than when hauling or push- 
ing in the manner just alluded to ; and in such 
cases they cannot do as much per day. Thus, 
in turning a winch or crank like that of a grind- 
stone, or of a crane, the continual bending of 
the body, and motion of the arms, is more fa- 
tiguing. The size of a winch should not exceed 
18 inches, or the radius of a circle of 3 ft. di- 
ameter ; and against it a laborer can exert a 
force of about 16 lbs., at a velocity of 2} ft. per 
second, or 150 ft. per minute, making very 
nearly 16 turns per minute ; for 8 hours per 
day. To these 8 hours an addition must be 
made of about \ part, for short rests. Or if a 
ivorking day is taken at 8, or 10, etc, hours, j 
part must generally be taken from it, for such 
rests. On the foregoing data an hour's work of 
60 minutes of actual hoisting would be 

lbs. ft. min. 

16X150X60=144,000 ft. 
or, deducting ^ part for rests, 115,200 ft. lbs. 
per hour of time, including rests. In practice, 
however, a further deduction must be made for 
the friction of the machine, and for the weight 
of the hoisting chains ; and in case of raising 
water, stone, ore, etc., from pits, for the weight 
of the buckets also. As a rough average we 
may assume that these will leave but 100,000 



Practical Catechism. 241 

ft. lbs. of paying, or useful work per hour; 
that is, that a man at a winch will actually lift 
equivalent to 100,000 lbs. of water, ore, etc., 1 
foot high per hour's time, including rests. This 
is equal to 1666f ft. lbs. per minute of a day 
of 10 hours, including rests. Therefore, in a 
day of 10 working hours he would raise 1,000,- 
000 lbs. net, 1 foot high ; or just y 1 -^ part of what 
a horse would do with a gin in the same time. 
We have before seen that in hauling along a 
level road, he can at a slow pace perform about 
i of the duty of a horse. He can also work the 
winch with greater force, say up to 30 or even 
40 lbs. ; but he will do it at a proportionately 
slower rate ; thus, accomplishing only the same 
daily duty. With a gin, like those for horses, but 
lighter, with two or more buckets, a practised 
laborer will in a working day of 10 hours, raise 
from 1,200,000 to 1,400,000 ft. lbs. net of water, 
ore, etc. With a shallow well or pit, more time 
is lost in emptying buckets than in a deep one ; 
but the deep one will require a greater weight 
of rope. To save time in all such operations on 
a large scale, there should be at least two buck- 
ets ; the empty one will be filled while the full 
one is being emptied. Is is also best to employ 
two or more men to hoist at the same time, by 
winches, at both ends of the axis ; and the men 



242 



Practical Catechism. 



will work with more ease if the winches are at 
right angles to each other. Each winch handle 
may be long enough for two or three men. An 
extra man should be employed to empty the 
buckets. He may take turns with the hoisters. 
The same remarks apply in some of the 
following cases: 

On a treadwheel a practised laborer will do 
about 40 per cent, more daily work than at a 
winch, or in a working day* of 10 hours, in- 
cluding rests, he will do about 1,400,000 ft. lbs. 
And he can do this whether he works at the 
outer circumference of the wheel, stepping upon 
foot-boards, or tread-boards, on a level with its 
axis, or walks inside of it near its bottom. In 
both cases, he acts by his weight, usually about 
130 to 140 lbs. ; and not by the muscular 
strength of his arms. When at the level of the 
axis, his weight acts more directly than when 
he walks on the bottom of the wheel ; but in 
the first case he has to perform a slow and 
fatiguing duty resembling that of walking up a 
continuous flight of steps ; while in the second 



*The working day must be understood to include 
necessary rests, and such intermissions as the nature 
of the work demands ; but does not include time lost 
at meals. A working day of ten hours may, therefore, 
have but 8, 7, or 6 etc., hours of actual labor. This will 
be understood if we hereafter speak of a working day, 
or simply a day. 



Practical Catechism. 243 

he has, as it were, merely to ascend a very 
slightly inclined plane ; which he can do much 
more rapidly for hours, with comparatively lit- 
tle fatigue ; and this rapidity compensates for 
the less direct action of his weight. Therefore, 
in either case, as experience has shown, he ac- 
complishes about the same amount of daily 
duty. Treadwheels may be from 5 to 25 feet in 
diameter, according to the nature of the work. 
They are generally worked by several men at 
once, and may at times be advantageously used 
in pile-driving, as well as in hoisting water, 
stone, etc. 

By a good common pump, properly propor- 
tioned, a practised laborer will in a day of ten 
working hours raise about 1,000,000 ft. lbs. of 
water, net.* 

Baling with a light bucket or scoop, he can 
accomplish about 2,005,000 ft. lbs. of water, net. 
By a bucket and swape (a long lever rocking 
vertically, and weighted at one end so as to bal- 
ance the full bucket hung from the other ; often 
seen at country wells) 600,000 to 800,000. In 
the last he has only to pull down the empty 
bucket, and thereby raise the counterweight. 



* Desagulier's estimates of daily work of men and 
horses exceed the above, but are entirely too great. 



244 Peactical Catechism. 

By two buckets at the ends of a rope suspended 
over a pulley, 500,000 to 600,000. Here he 
works the buckets by pulling the rope by hand. 

By a tympan, or tympanum,* worked by 
treadwheel, about 1,200,000 to 1,400,000. 

By a Persian wheel, t a chain pump, a chain 
of buckets,! or an Archimedean screw, all 
worked by a treadwheel, from 800,000 to 1,000,- 
000 ft. lbs. Of these four, the first three lose 
useful effect by either spilling, leaking, or the 
necessity for raising the water to a level some- 
what higher than that at which it is dis- 
charged. 

When any of the five foregoing machines are 



*The tympanum revolves upon a horizontal shaft- 
and is a kind of large wheel, the spokes, arms or radii 
of which are gutters, troughs or pipes, which at their 
outer ends terminate in scoops, which dip into the 
water. As the water is gradually raised, it flows along 
the arms of the wheel to its axis, where it is discharged. 
The scoop wheel is a modification of it. It is an ad- 
mirable machine for raising large quantities of water 
to moderate heights. 

| A kind of large wheel with buckets or pots at the 
ends of its radiating arms ; revolves on a horizontal 
axis, discharges at top. The buckets are attached 
loosely, so as to hang vertically, and thus avoid spilling 
until they arrive at the proper point, where they come 
into contact with a contrivance for tilting and empty- 
ing them. The noria is similar, except that the buck- 
ets are firmly held in place, and thus spill much water. 
It is therefore inferior to the Persian wheel. 

J An endless revolving vertical chain of buckets. 
D'Aubuisson and some others erroneously call this the 
noria. It is an effective machine. 



Practical Catechism. 245 

worked by men at winches, the results will be 
about J less than by treadwheels. They are all 
frequently worked also by either steam, water 
or horse power. 

By walking backwards and forwards, on a 
lever which rocks on its center, a man may, ac- 
cording to Robinson's Mechanical Philosophy, 
perform a much greater duty than by any of 
the preceding modes. Robinson states that a 
young man weighing 135 lbs., and loaded with 
30 lbs. in addition, worked in this manner 
for ten hours a day without fatigue ; and raised 
9J cubic feet of water 11 J feet high per minute. 
This is equal to 3,984,000 foot lbs. a day of ten 
hours; or 6640 foot lbs. per minute; or nearly 
4-10 of the net daily work of a horse in a gin. 

A laborer standing still can barely sustain for 
a few minutes a load of 100 lbs. by a rope over 
his shoulder, and thence passing off horizon- 
tally over a pulley. And scarcely as much, 
when (facing the load and pulley) he holds 
the end of a horizontal rope with his hands be- 
fore him. He cannot push horizontally with 
his hands at the height of his shoulders, with 
more than about 30 lbs. force. 

AVeisbach states from his own observation, 
that four practised men raised a "dolly" (a 
wooden beetle or rammer of wood, with four 



246 Practical Catechism. 

horizontal projecting round bars for handles) 
weighing about 120 lbs., four feet high at the 
rate of 34 times per minute, for 4J minutes ; 
and then rested for 4J minutes ; and so on alter- 
nately through the ten hours of their working 
day. Therefore, five of these hours were lost 
in rests ; and the duty performed by each man 
during the other five hours, or 300 minutes, was 

120x4x34x300 

=1,224,000 ft. lbs. 

4 

In the old method of driving piles, where the 
ram of 400 to 1200 lbs. suspended from a pulley, 
was raised by 10 to 40 men pulling at separate 
cords, from 35 to 40 lbs. were allotted to each 
man ; to be lifted from 12 to 18 times per min- 
ute, to a height of from 3| to 4J feet each time, 
for about 3 minutes at a spell, and then 3 min- 
uies rest. It was very laborious; and the 
gangs had to be changed about hourly, after 
performing but half an hour's actual labor. 

Q. How much work will the evaporation of 
one cubic inch of water, at a pressure of 14.7 
lbs. per square inch, do ? 

A. One cubic inch of water evaporating at 
14.7 lbs. per square inch, and making 1,641.5 
cubic inches of steam at 212 deg. Fahr.=100 
deg. C, would, if in a vertical cylinder of one 



Practical Catechism. 247 

square inch bore, raise the 14.7 lbs. 1,641.5 — 1 
= 1,640.5 inches=136.7 feet, doing 14.7x136.7 
= 2,009.49 foot lbs. of work (not allowing for 
friction nor for weight of piston). 

Q. How much work will a good windmill do 
in a day, raising water ? 

A. An 8 2 foot wheel will raise 3,000 gallons 
of water daily a distance of 25 feet. Its first 
cost, including pump and a plain tower, is about 
$150. A 10 foot wheel will raise about 9,000 
gallons of water a day a like distance, and cost 
about $180, including the appurtenances above 
mentioned. A 12 foot wheel will raise 16,000 
gallons of water per day the above distance, and 
cost with the same appurtenances §210 ; so up 
from 14 to 16, 18 to 20 feet diameter of wheel 
until we reach a 25 foot wheel, which costs 
about $1,200 and will raise 100,000 gallons of 
water daily the specified distance. 

miscellaneous. 

Q. How do you test the accuracy of a pair of 
paper making rolls ? 

A. Take a strip of steel a foot long, half an 
inch wide, an eighth thick ; fasten it to a strip 
of wood and run it through an emery surfacer so 
that its thickness will be reduced with a regu- 
lar taper, from one-eighth inch to nothing. 



248 Peactical Catechism. 

Graduate its face to half inches. Set the rolls 
together; revolve them, and draw on one of 
them, while turning, circumferential chalk cir- 
cles a foot apart. Stop them and mark with 
chalk on the ends the tangent points. Pass the 
tapered strip between the rolls at the circles 
and record the distance to which they enter; 
thus Al, f"; A2, f"; A3, f'j and so on. 
Then turn the rolls a quarter turn ; pass in the 
strip as before, and record the depths thus : — 
B If ; B 2f ; B 3f . Do the same thing with 
the other quarter points. The distances to 
which the strip passes should be all alike, both 
endwise and circumferentially. Excessive pen- 
etration indicates a low spot. This may be 
located on either the upper or the lower roll by 
turning only that roll and making its record, 
using as a standard the same straight lines on 
the other rolls. 

When the distribution of the paper stock is 
accurate, the rolls may be proved correct or 
incorrect by marking the paper off in squares of 
four or five inches each and calipering them 
between surfaces having at least a square inch 
of area. The thicknesses either at each inter- 
section of lines, or in the center of each square, 
should be marked. A recurrence of the same 
excessive thickness or thinness at regular 



Practical Catechism, 249 

intervals (say the circumference of the rolls) 
points out that there is a low or a high spot on 
at least one of the rolls, at a point in its length 
indicated by the distance of the thick or thin 
place on the paper, from its edge. 

These two tests should confirm each other. 
The one described second should be made first. 

Q. How can the speed of a propeller balloon 
be determined ? 

A. Poles' rule is that the useful horse-power 
of the engines applied to the screw shaft should 
be equal to 0.00193 times the square of the 
maximum diameter of the balloon in feet, times 
the cube of the desired velocity in feet per sec- 
ond, divided by 3850. At that rate, the veloc- 
ity should be the cube root of 3850 divided by 
the cube root of 0.00193 times the square of the 
diameter ; or what is the same thing, the cube 
root of the quotient got by dividing 3850 by 
0.00193 times the square of the diameter. Tiss- 
andier had a balloon 30 feet in diameter with a 
lh h. p. dynamo, and the rule would give for 
this 14.9 ft. per second. The actual velocity 
was 13.1 ; but the screw was very small. Ke- 
nard & Krebs had a 27.5 ft. balloon with a 2.33 
horse power motor. This should and did give 
about 18.3 ft. per second or 12.5 miles per hour. 
With the horse power increased to 3.5, which 



250 Practical Catechism. 

should give 21 feet per second (14.3 miles per 
hour) the actual speed was 14.6 miles. 

Q. " What is the pressure of the sea at great 
depths, as, for instance, a mile or two ? " 

A. A column, one mile deep, of water, weigh- 
ing 62.4 lbs. per cubic foot, presses on its base 
almost exactly one gross ton per square inch 
(fresh water, 2,192 lbs., sea water, 2,347.5 lbs). 

Q. What is the best way to observe vibra- 
tions of the earth made by passing trains, 
wagons, etc. ? 

A. Put a box holding about twenty lbs. of 
mercury thickened by amalgamation with tin, 
upon a heavy plank screwed to the top of a 
post sunk about six feet into the ground ; then 
observe by a telescope, images reflected in the 
surface of the mercury. 

Q. What should be done with a person over- 
come with illuminating gas ? 

1. Take the man at once into the fresh air. 
Don't crowd around him. 

2. Keep him on his back. Don't raise his 
head or turn him on his side. 

3. Loosen his clothing at his neck. 

4. Give a little brandy and water, not more 
than four tablespoonfuls of brandy. Give the 
ammonia mixture (one part of good aromatic 
ammonia to sixteen parts water) in small quan- 






Practical Catechism. 251 

tities at short intervals, a teaspoonful every two 
or three minutes. 

5. Slap the face and chest with the wet end 
of a towel. 

6. Apply warmth and friction if the body or 
limbs are cold. 

7. If the breathing is feeble or irregular, arti- 
ficial respiration should be used, and kept up 
until there is no doubt that it can no longer be 
of use. 

8. Administer oxygen. 

Q. How can cork be cut smoothly ? 

A. With a greased knife. 

Q. How are cork pen-holders made ? 

A. By roughing them out with a very sharp 
knife and then grinding them to shape with an 
emery wheel. 

Q." Do climbing plants like ivy make walls 
damp, or not ? " 

A. Woodbine and ivy on brick buildings ab^ 
sorb all moisture there is in the bricks and mor- 
tar, and the presence of the foliage acts as a 
shield, turning severe driving rains away from 
the walls. The vines derive most of their sus- 
tenance from the ground, and do not give out 
moisture from the rootlets that cling to the 
wall. 

Q. " Why is it that oil tanks in the oil re- 



252 Practical Catechism. 

gions are so often struck by lightning and de- 
stroyed, when they are well protected by light- 
ning rods — in fact, surrounded by them ? " 

A. " One of the principal reasons, if not the 
only reason, why oil tanks are so frequently 
struck by lightning and destroyed, is that the 
rods which are intended to protect them are 
separated from the body of the tank and not 
directly connected with it. The result is that 
whenever an electric accumulation occurs in the 
neighborhood sufficient to cause a disruptive 
discharge upon the tank, the spark takes the top 
of the rods first, but instead of continuing along 
the rods to the earth, flies to the metallic body 
of the tank, which is in so much better connec- 
tion with the earth ; or a spark may leap from 
the tank to the rods by reason of the enormous 
inductive influence of so huge a mass of metal. 
In either case the passage of a spark is liable to 
explosively ignite the oil vapor present around 
the tank, or the lighter portions of the oil at the 
top of the tank. The proper method, we are con- 
vinced, is to attach a number of rods substan- 
tially directly to the body of the tank itself, and 
carried up high enough to be above the gas ris- 
ing from it — say about 30 feet — and there 
united. They should also be provided with a 
good earth connection. The best form for such 



Practical Catechism. 253 

rods would be flat iron or copper bands or bars, 
which should be so fastened to the sides of the 
tank as to form a good metallic connection with 
it ; at least four or six such bars should be used 
in the manner here suggested." 

W. H. Wahl. 

Q. What is the initial velocity of a ball in a 
cannon ? 

A. In the YVhitworth gun, 1300 feet per sec- 
ond ; this being generated in 2^0 second. 

Q. How may pencil drawings be made inef- 
faceable ? 

A. By blowing on them with an atomizer a 
spray of solution of gum mastic in absolutely 
pure alcohol. Passing over them a soft flat 
brush dipped in milk, will do the same thing in 
less degree, but there is some danger of spoiling 
the drawing, if executed with a very soft pencil 
and light touch. 



INDEX 

TO 

PKACTICAL CATECHISM. 



An asterick (*) signifies that there is an illustration. 

ABSORPTION of water by bricks, 20; by building 
stones, 36. 

Acids, 142. 

Acid, carbolic, as a disinfectant, 63. 
" carbonic, exhaled by a man, 221 ; allowable pol- 
lution by, 221 ; in plants, 185. 

Acid, sulphurous, as a disinfectant, 63. 
,' sulphuric, for oil bleaching, 51. 

Acidity of wines, 235. 

Age, effect of upon mortar, 138. 

Adult, air required by, 221. 

Air, 1 ; action of upon wood, 168 ; ascension of in mine 
shafts, 223 ; compressed, heat of, 119 : density of, 
3,6 ; discharged by a ventilator, 221; flow of in 
pipes and conduits, 224 ; for oil bleaching, 51 ; 
horse power to draw, 225; motive column of in 
mine shafts, 226; pressure of, 1; rarefied, for 
transmitting power, 189 ; required by an adult, 
221 ; volume of, 3, 4, 5, 6 ; weight of, 1. 

Air-dried cores, 77. 

Alabaster, 34. 

Alba Flora wine, alcohol in, 236. 

Alcohols, 238. 

Alcohol as an antiseptic, 62 ; in wines and liquors, 235 ; 
testing for purity, 55. 

Ale, alcohol in, 236 ; as a force producer, 69. 

Alloys, 6, 7, 8, 11 ; antifriction, 10 ; for condenser tubes, 
10; of zinc and tin, expansion of, 156; melting 
point of, 8; separation of components in, 7; 
strength of, 8 ; temperature of making, 12. 

Alloying, 11. 



256 Index. 

Alumina in fire bricks, 27. 

Aluminum alloys, 10; bronze, 10; burnishing, 152; 
characteristics of in melting, 158 ; cold rolling, 
156; engraving, 152; finishing, 153; grinding, 
152; lathe work on, 152; melting point of, 158; 
polishing, 151; soldering, 199; specific weight of, 
157 ; spinning, 153 ; whitening, 58. 

American bricks, 23 ; flours, 67. 

" woods, strongest, 213 ; heaviest, 214. 

Amontillado, alcohol in, 236. 

Amyl alcohol, detection of, 238. 

Angle of repose, 32. 

Aniline, to detect in iron paints, 166. 

Animal charcoal for oil bleaching, 52. 

" oils, test for, 142; for giving body to lubri- 
cants, 140. 

Animal sugar, 205. 

Annealing steel, 110. 

Anthracite, coking, 93 ; as fuel, value of, 90. 

Antifriction curve for bearings, 144, 145. 
" alloys, 10. 

Antimony in lead alloys, 8. 

Antiseptics, 61, 62. 

Apple wood, swelling of, 173, 

Apples as force producers, 69, 

Arch bricks, 20. 

Archimedean screw pump, work done at, 244. 

Areas, estimating by weight, 42. 

" of circles, 38 ; of chimneys, 61 ; of irregular fig- 
ures, 41* 42;* measuring by planimeter, 39; of 
trapeziums, 38 ; of triangles, 39, 40 ; of tuyeres, 81. 

Arrowroot as a force producer, 69. 

Arsenic as an antiseptic, 62. 

Ash wood, shrinkage of, 174 ; swelling of, 173. 
" tobacco, amount taken from the soil, 238. 

Askew on steel welding, 130. 

Asphalt for iron tank paint, 163 ; for tank lining, 55 ; 
preserving, elasticity of, 31 ; roofs of, 31. 

Atmosphere, for welding, 125 ; pressure of, 1. 

BABBITT'S metal, composition of, 13. 
Baking, loss of meats in, 70. 
Balances, fraudulent, to detect, 233. 
Ball and socket steam joints, 148. 
" cannon, initial velocity of, 252. 



Index. 257 

Ball room floors, loads for, 30. 

Balls, to cast, 73. 

Ballast, porous, 192. 

Balloons, horse power for, 249 ; lifting capacity of, 106 ; 

speed of, to estimate, 249. 
Baltimore bricks, dimensions of, 23. 
Band saw detachable, 196 ; tension upon, 196. 

" " mill, capacity of, 197, 198. 
Bark, allowance for in measuring timber, 32. 
Barmng iron, 177. 
Barsac, alcohol in, 236. 

Bateman's rule for cast iron pipe, thickness, 48. 
Bath for hardening mill picks, 112. 
Ban me scales, 234. 
Bay wood, 218. 
Beams. 14 ; breaking weight, 14 ; building up, 215 ; cast 

iron, 18; flange, 17; crane, strength of, 15, 1,18; 

iron, 17, 18; shrinkage in casting, 83; T.17. 
Bearings, cup, 144; cylindrical shaft, 143; flat shaft, 

143 ; hemispherical, 144 ; machinery, metal for, 

14; marine engine, pressure upon, 141; Schiele's 

curve, 144, 145; shaft, vertical, 144; pressure 

upon, 141 ; vertical shaft, 143. 
Beech, shrinkage of, 174; swelling of, 173. 
Beef, loss in cooking, 70. 
" suet for spring hardening, 111. 
* tea, how to make, 70. 
Beers, 23*; alcohol in, 236. 

" and wines, distinction between, 236. 
Beer, amount from one bushel of malt, 238. 

41 process for wood preserving, 165. 
Beet sugar, 206. 
Bells, alloy for, 14. 
Belt cement, composition of, 19. 
Belt dressing, 19. 

" leather, tenacity of,"19 ; leather, weight of, 18. 
Belts, cleaning, 19;* cotton, 18; hemp, 18; leather, 

dressing of, 19; leather, safe working strain, 19; 

strength of, 18. 
Bending timber, steaming for, 215. 
Bessemer rail, life of, 192. 

" steel, theory of making, 127. 
Bethel process for wood preserving, 165. 
Beton-Coignet, 138. 
" walls, their concrete qualities, 36. 



258 Index. 

Bilge water, to neutralize its corrosive action, 163. 

Bismuth, shrinkage in casting 83. 

Bituminous coal, proportion of carbon in, 93. 

Blazing off springs, 111. 

Birch, swelling of, 173. 

Black paint for smoke stacks and boiler fronts, 162. 
" pigment, 166. 
11 lead, see graphite, 83. 

Blackening cores, 77. 

Blast for coke in iron melting, 81. 

Bleaching oils, 51. 

Blow holes, caused by chaplets, 75 ; in steel ingots, to 
prevent, 126. 

Body bricks, 20. 

Boiled oil, to make, 171. 

Boilers, steam cylindrical foot in measuring, 44 ; iron, 
cement for, 50 ; composition to prevent rusting, 
164 ; steel for, 109. 

Boiler fronts, black paint for, 162. 
" shells, leakage of, 49. 

Boiling in oil, 69. 

" loss of meat in, 70. 

Bone, saw teeth for, 195.. 

Borax as a flux, 66 ; as a wood preserver, 165 ; for braz- 
ing cast iron, 200 ; for welding steel, 110. 

Boucherie process for wood preserving, 165. 

Bordeaux wine, alcohol in, 236. 

Box, swelling of, 173. 

Boxes, line shaft rebabbitting, 146. 

Brandy, alcohol in, 236; potato, flavoring matter in, 
237. 

Brass castings, shrinkage of, 82. 
" gear wheels, 101. 
" hardening, 11. 

" malleable, 12; mercury in, 13; shrinkage in cast- 
ing, 83. 
" pipes, squirting, 8. 

11 to color, 59, 60; to redden, 59; to stain, 59; to 
water, 60; to whiten, 59; white, 13; weight of, 
157 ; yellow, 13. 

Brazing cast iron, 200. 

Bread as a force producer, 69. 

Bread, flour for, 66; stale, to make fresh, 68; wet, 
water in, 68. 

Barking felled trees, 215. 






Index. 259 

Breaking weight of beams, 14. 

Bricks, 22; absorption of water by, 20; building, 19; 
dimensions of, 23: fire, injurious effects of, 26; 
per square foot or wall, 23; pressure borne by, 
20 ; strength of, 20 ; test for, 20. 
Brick layer, work per hour, 23. 

" work, 22 ; angle of repose of, 33 ; corners in, 24 ; 

courses how to run, 22 ; influence of mortar upon 

strength of, 21; joints in, 25; mortar in, 24; 

weight of, 22 ; permissible strain on, 21. 

Bridge walls, fire bricks in, 29 ; how to lay, 27 ; joints 

for, 27. 
Bridges, concrete, advantages of, 30. 

" strength of, 15 ; steel for, 109 ; steel, loads for, 
30. 
Bright work, shipping, 162 ; to protect from rust, 162. 
Bronze, aluminum, 10. 

" cannon, the increasing hardness, density and 

elasticity of, 10. 
M gun, 9 ; hardening, 11 ; phosphor, for worm 
wheels, 151. 
Bronzes, strongest of, 9. 
Bronze, tempering annealed, 113. 

" weapons, phosphorus in, 11 ; from Troy, 11. 
white, 12. 
Browning gun barrels, 58. 
Bronzing zinc, 58. 
Bouquet of wine, 237. 
Buff calcimine, 185; paint, 170.* 
Building, 27. 

" bricks, 19. 

" house, woods for, 220. 

" materials, angles of repose of, 33 

oak for, 218. 
" paper, water proof, 29. 
11 ship, woods for, 218. 

" stones, 34 ; disintegration of, 37 ; durability 
of, 36 ; iron in, 37 ; refractory, 36 ; water ab- 
sorbed by, 36. 
Building up beams, 215. 
Bule wood, 214. 
Burnettizing, 165. 
Burnishing aluminum, 152. 
Burning castings, iron for, 79. 
Bush hammering sand stone, 28. 



260 Index. 

Bushes, metals for, 14. 

Butter, volume and weight of, 71 ; as a force producer, 

69. 
Butyl alcohol, detection of, 238. 

CABBAGE as a force producer, 69. 
Cables, how laid up, 194. 
Cadmium, 7. 

Calcimine, coloring, 185 ; to make, 184. 
Calculations, 37. 
Californian flours, 67. 
Camphor as an antiseptic, 62. 
Cane sugar, 201. 

Cannon ball, initial velocity of, 252. 
Cannon, bronze, 10. 

Capacity for heat of water and quicksilver. 119. 
" of coal pockets, 43. 
" of various household measures, 72. 
" see under special heads. 
Carbolic acid as an antiseptic, 62 ; as a disinfectant, 

63. 
Carbonic acid, allowable pollution by, 221 ; exhaled by 

a man, 221 ; in plants, 185 ; liquefaction of, 209. 
Carbonic oxide, liquefaction of, 209. 
Carbon in iron 125 ; in steels, percentage of, 130 ; pro- 
portion or, in anthracite coal, 93 ; in bituminous 
coal, 93 ; in steel, 126. 
Carnation paint, 171. 
Carriages, how to keep, 175. 
Carrots as force producers, 69. 
Car weights, 192. 
Case hardening composition, 126. 

" hardening steel, 131. 
Casting beams, shrinkage in, 83. 
" cylinders, 75. 
'* girders, shrinkage in, 83. 
" heat of metal in, 73. 
" valve faces, 75. 
Castings, brass ; shrinkage, of, 82 ; burning, 79 ; con- 
traction in, 74 ; cooling of, 7 ; copper, shrinkage 
of, 82 ; copper, to make solid, 66. 
Castings dirty,toavoid,73; dry, shrinkage of,82; finding 
weight from pattern, 232 ; German silver, to make, 
66; green, shrinkage of, 82; gun metal, shrink- 
age of, 82; iron, 72, 73; iron, smooth, 83; iron, 



Index. 261 

Castings— 

stuffing, 123 ; iron, welding, 86 ; loam, shrinkage 
of, 82; malleable iron for, 86 ; malleable iron, to 
make, 86 ; mixed steel and iron, 82 ; shrinkage, 
74, 83 ; smooth, cores for, 77 ; weight of from pat- 
terns, 82. 

Castor oil as a belt dressing, 19. 

( ast steel gear wheels, 101. 
" steel, welding, 130. 
" iron beams, 17, 18. 

" iron, comparison with aluminum, 158 ; gear 
wheels, 101 ; mixing steel with, 82 ; pipes, thick- 
ness of, 47 ; rate of rusting, 177 ; strength of, 123 ; 
spherical shot, volume of, 45 ; shot, diameter of, 
46 ; tenacity of, 155 ; to braze, 200. 

Caustic soda lye for oil bleaching, 51. 

Cedar, swelling of, 173. 

Cellulose, dissolving, 29. 

Cements, 49, 135. 

Cement, belt, composition of, 19 ; for fire bricks, 27 ; 
for iron, 51 ; for iron boilers, 50; hydraulic, 136, 
137; Portland, 136; Portland in brick work, 21, 
25 ; Eoman, 136 ; Winchell's universal, 49. 

Centigrade scale, 206. 

Centrifugal machine for oil bleaching, 52. 

Ceresin, 179. 

Chafing, deduction for on ropes, 201. 

Chain pump, work done at, 244. 
" size for a given strain, 201. 

Chains, iron for, 125. 

Chalk, prepared, to make, 178. 

Champagne, alcohol in, 236. 

Chaplets, 75. 

Characteristics of good timber, 213. 

Charcoal as a deodorizer, 61, 63 ; for darkening flowers, 
186 ; for oil bleaching, 52. 

Charcoal iron for wire drawing, 125. 

Charcoal making, best age of wood for, 87. 

Charcoal, temperature of combustion of, 87. 

Charring wood by steam pipes, 87. 

Cheese as a force producer, 69. 

Cherry bricks, 20. 
stain, 180. 

Chester steel, 132. 

Chestnut paint, 170. 



262 Index. 

Chick pea as a life sustainer, 69. 

Chilian flours, 67. 

Chilled molds, casting in, 9. 

Chill, to increase depth of, 81. 

Chimney gases, volume of, 90. 

Chimneys, area of, 61 ; volume of brick work in, 25. 

Chimney walls, friction of, 61. 

China clay for oil bleaching, 52. 

Chisel steel, 131. 

Chloride of iron as an antiseptic, 62 ; as a disinfectant, 
63. 

Chloride of lime as a disinfectant, 61, 63. 

11 of tin for weighting silks, 52 ; as an antisep- 
tic, 62 ; as a disinfectant, 63 ; as a wood pre- 
server, 165 ; for oil bleaching, 52. 

Chlorine test for oils, 143. 

Chocolate color paint, 170. 

Chrome steel, tempering, 111. 

Church bells, alloy for, 14. 
" floors, loads for, 30. 

Cider, alcohol in, 235. 

Cinnamon tree, 186. 

Circles, diameters, areas of, 38. 

Circular saw blade, 195. 

Circular saws, inserted teeth for, 194 ; set for, 194 ; two- 
high, 195. 

Civil engineer, cylindrical foot for, 44. 
" " the term, 153. 

Claret, alcohol in, 236. 

Clarification of oils, 51. 

Clarke's rule for cast iron pipe, thickness, 48. 

Clay as a deodorizer, 63 ; for oil bleaching, 52. 

Climbing plants, effect of upon walls, 251. 

Clinker bricks, 22. 

Clock dials, tower, to gild, 165. 

Coal and coke mixing for iron molding, 80. 

Coal, effect of hydrogen upon, 90 ; for heating given 
lengths of pipe, 114 ; heating power of, 92 ; horse 
power from one pound, 94 ; in melting iron, 79 ; 
number of cubic feet per ton, 43 ; proportion of 
to iron in reheating furnaces, 88 ; screening, 73. 

Coal pocket, capacity of, 43. 
" tar for slate roofs, 29. 

Cocoa as a force producer, 69. 

Cod liver oil as a force producer, 69. 



Index. 263 

Coefficient of friction, 33 ; effect of pressure upon, 143. 
Coke and coal mixing for iron melting, 80. 

" for oil bleaching, 52 ; in melting iron 79 ; blast 
for in iron melting, 81 ; to remove sulphur from, 
87. 
Coking anthracite, 93. 
Colares wine, alcohol in, 236. 
Cold cores for green sand molds, 77. 

" greatest produced, 209 ; intense, to produce, 209. 

M producing mixtures, 210, 211, 212. 

44 rolled shafting, 124. 

u rolling aluminum, 157 ; hard iron, 132 ; hard steel, 
132 ; iron, 124 ; soft puddled iron, 132. 

44 short steel, 128. 
Colobaugh bricks, 23. 
Coloring brass black, 60 ; copper color, 60 ; dark 

bronze, 60. 
Color mixing, combinations in, 169. 
Colors of rivers, 228. 
Combinations in color mixing, 169. 
Combustion gases, temperature of with originator, 88. 
Combustion of charcoal, temperature of, 87. 
Compositions, see under process for which they are de- 
sired. 
Compress, cotton, designing, 151. 
Compressed air, heat of, 119. 
Compressing steel, 132. 
Compression of metals, 112. 

Compressive strength of dry and wet woods, 218. 
Concrete, 135. 

44 bridges, advantages of, 30. 

44 swelling in setting, 137 ; volume of compared 

with gravel, 138. 
Concrete walls, their fire proof qualities, 36. 
Condenser tubes, proportion of alloy for, 10. 
Conduits, flow of air in, 224. 
Connecting rods, strength of, 148. 
Consolidation locomotives, 139. 
Constantin wine, alcohol in, 236. 
Consumption of oil, estimating, 142. 
Contraction in castings, 74. 
Contracts for masonry, 29. 
Cooking in oil, 69. 
Cooling of castings, 7. 
Copper alloys, 10, 13. 



264 



Index. 



Copper castings, shrinkage of, 82 ; solid, to make, 66. 
" effect upon steel, 129; fastenings for wooden 
vessels, 64. 
Copper-ferromanganese alloys, 12. 
" fire box stays, hollow, 148. 
" hydrated carbonate of, 8. 
Coppering iron, 177 ; zinc, 59. 

Copper in lead alloys, 8 ; melting point of, 155 ; shrink- 
age in casting, 83. 
Copper sulphate as a wood preserver, 165. 
Copper-tin alloys, 11. 

" weight of, 157 ; worked, tenacity of, 155. 
Copper-zinc alloy for condenser tubes, 10. 
Copying ink, 55. 

Coquina, Florida, durability of, 37. 
Cordage, effect of tar upon, 194 ; strength of, 194. 
Cores, air dried, 77 ; allowance for weight of in pat- 
terns, 232 ; blackening, 77 ; gas in making, 76 ; 
lifting pressure of, 79 ; making, 76 ; thin, baking, 
76 ; venting, 76. 
Cork, how to work, 251. 
Corn cobs for oil bleaching, 52. 
Corners in brick work, 24. 

Corrosion of iron, 163 ; of iron ship bottoms, to pre- 
vent, 163. 
Corrosive action of bilge water, 163. 

" sublimate as an antiseptic, 62. 

Corrugated iron lining for elevator shafts, 30. 

" roofs, weight of, 30. 

Cotton belts, 18. 

" compress, designing, 151. 
" press, geared, 103. 
" wadding for oil bleaching, 52. 
Counter, revolution, Meigs, recording, 146. 
Course masonry, proportion of headers in, 28 ; strength 

of, 28. 
Covering power of paints, 167. 
Cracking of steels in hardening, 109. 
Cracks in wood, mixture for filling, 172 ; varnish, sci- 
ence of, 168. 
Crane beams, strength of, 15. 

Crane, calculating turns of handle, 188 ; work with, 188. 
Crank, work done in turning, 187, 240. 

" pins, 141 j lubrication of, 143; pressures upon, 
141. 



Index. 265 

Cream paint, 169. 

Creosote as an antiseptic, 62 ; as a disinfectant, 63 ; as a 
wood preserver, 165. 

Croton bricks, 23. 

Crucible steel, manganese in, 126 ; temperature of mak- 
ing, 127. 

Crucibles, to make them last, 11. 

Crushing strength of masonry walls, 36. 

Crystallization of iron by vibration, 124. 

Cup bearings, 144. 

Cupola, melting steel in an ordinary, 82. 

Currant wine, alcohol in, 236. 

Current meter, 122. 

Curve, antifriction for tractrix bearings, 144, 145. 

Customary measuring of standing timber, 32. 

Cutting woods, proper age for, 214 ; cork, 251. 

Cylinders, casting, 75 ; shrinkage of in casting, 83 ; 
volumes of, 44. 

Cylindrical foot, 44 ; for engines and water works, 44. 
" " of water, weight of, 44. 

" shaft bearings, 143. 

DAHLIAS, darkening, 186. 
Dam for measuring stream flow, 121. 

Daniell's pyrometer, 207. 

Darkening dahlias and other flowers. 186 ; of woods, 
220. 

Day's work, plowing, 30 ; standard for laborer, 239. 

Dead oil as a wood preserver, 165. 

Decay in wood, cause of, 168. 

Density of air, 3, 6 ; of iron and steel affected by jar- 
ring, 134 ; of steel, effect of hardening upon, 110 ; 
of tempered steel, adjusting, 134. 

Deodorizers, 61, 63. 

Deodorizing various substances, see under special 
heads, 57. 

Designing cotton compress, 151. 

Deserts, travelling in, food for, 69. 

Destroying smells, 63. 

Dials, tower clock, to gild, 165. 

Diameter of driving shafts, 190 ; of circle of given area, 
38. 

Dimensions, see under special heads. 

Direct process of steel making, 127. 

Dirty castings, to avoid, 73. 



266 Index. 

Disguising smells, 62. 

Distance between rails, 191. 

Distemper, to make, 171. 

Disinfectants, 61, 63. 

Disintegration of sand stone, 34 ; of building stones, 37. 

Distinguishing steels, 129. 

Door openings, measuring, 28. 

Doors, fire proof, 30. 

Doughing, water taken up by flour in, 68. 

Drab paint, 170. 

Drawing nails and spikes, 63. 

Drawing power of chimneys, 60. 

Drawings, pencil, to make inerasable, 252. 

Dressing for leather belts, 19. 

Driving nails, 63. 

Driving shaft, diameter of, 190 ; horse power of, 190. 

Dry earth, angle of repose of, 33. 

Dryer, to make.171. 

Drying molds, 76. 

Dry rot, 216 ; cause of, 169. 

Dry sand castings, shrinking of, 82. 

" wood, compressive strength of, 218. 
Dry works, woods for, 218. 
Ductility of iron, 124, 126; of metals, order of, 155; of 

tempered steel, adjusting, 134. 
Durability of building stones, 36 ; of Florida coquina, 

37 ; of Portland sandstone, 37. 
Dusting moulds, 79. 
Dwelling floors, loads for, 30. 

EAETH, infusorial, for oil bleaching, 52. 
Earth, angle of repose of on various materials, 33. 
Earth weighing, 105 ; vibrations of, to observe, 250. 
East light, quality of, 177. 
Ebony, swelling of, 173. 
Economy of fuel in iron moulding, 80. 
Eggs, weight of, 71 ; white of, as a force producer, 69. 
Egyptians, ancient, art of hardening brass and bronze, 

11. 
Elastic limit of iron, 132. 
Elasticity of iron, 126. 
Elastic resistance of iron, 132; woods, 218. 
Elder wine, alcohol in, 236. 
Elevator shafts, making fire proof, 30. 



Ikdex. 267 

Elm, shrinkage of, 174. 
Enamel leather, to keep, 175. 
Enamelling cast iron water pipes, 57. 
Endogenous trees, 214. 
Engine beams, shrinkage in casting, 83. 
Engineer, mechanical, the term, 153. 
Engineer and machinist, the term, 153. 
English flours, 67. 

11 Portland cement, 136. 
Engraving aluminum, 152. 
Essential oils as antiseptics, 62. 
Ethers, potato and wood, 239 ; difference between them 

and spirits, 238. 
Ethylene, liquefaction of, 209. 
Evaporation of water, work done by, 246. 
Everlasting whitewash, 183. 
Expansion of materials by heat, see under special 

heads. 
Expansion of railway rails, 191 ; of steels in hardening, 

110. 
Exposures best for paintings, 169. 

FACTORY floors, loads for, 30. 
Fading of woods, 220. 
Fahrenheit scale, 206. 
Falling bodies, calculations of, 107; striking velocity 

of, 109. 
Fastenings, 63. 
Fat meats, salt in, 71. 
Fat of beef as a force producer, 69. 
Faults of woods, 217. 
Fawn color paint, 170. 
Feeding heads, 73. 
Felspar building stone, 36. 
Felt for oil bleaching, 52. 
Ferro-manganese alloys, 12. 
Fibre of wrought iron, 123. 
Figures, oil, 142. v 

File steel, 130. 

Files, to keep from rusting, 161. 
Fillets, 73. 
Filling wood, 173. 
Filtering for oil bleaching, 52. 
Fine masonry, strength of, 28. 
Fine sand for cores, 77. 



268 Index. 

Finishing aluminum, 153. 

Fir, shrinkage of, 174 ; swelling of, 173. 

Fire box stays, hollow copper, 148. 

Fire bricks, 26 ; laid in cement, 27 ; in bridge walls and 
furnace linings, 27. 

Fire brick laying, capacity of a workman, 27. 

Fire, effects of upon lime stone, 36. 

Fire proof doors, 30 ; whitewash, 182. 

Fire stones, injurious constituents in, 34. 

Fish as a force producer, 69. 

Fish oil for steam boilers, 164. 

Flange beams, 17. 

Flash point of mineral lubricants, 140. 

Flash weights, 78. 

Flat pitched slate roofs, 29. 

Flat shaft bearings, 143. 

Flavoring matter in potato brandy, 237. 

Flexible mucilage, 49. 

Flints, angle of repose of, 33. 

Floors, darkening, 186. 

Floor loads, maximum, 30. 

Floors, paints for, 181 ; waxing, a good mixture for, 
178. 

Flours, 66, 67 ; for blending, 67. 

Flour, angle of repose of, 33 ; in core making, 76, 77 ; 
test for, 67 ; water taken up by, 68 ; wheat, vol- 
ume and weight of, 71 ; volume and weight of, 71. 

Flow of water in a stream, 120 ; through a hole, 120. 

Fluxes, 65. 

Flux for steel, Plaster of Paris as, 130 ; for welding 
steel, 110. 

Fontignac, alcohol in, 236. 

Foods, 66 ; as force producers, value of, 69 ; volume and 
weight of, 71. 

Foot, cylindrical, 44. 

Force of screw, 43. 

Force producers, various foods as, 69. 

Forging large masses of iron and steel, 133. 

Fouling of iron ship bottoms, to prevent, 163. 

Foundations, for brick walls, 25 ; sand stone for, 34. 

Foundry practice, 72. 

Fracture of iron and steel, effect of temperature and 
speed upon, 134. 

Friction, coefficient of, 33 ; coefficient of, effect of press- 
ure upon, 143. 



Index. 269 

Friction in journals in starting, 143 ; loss of by gear 

wheels, 101 ; of chimney walls, 61 ; of screw, 43. 
Fruit sugar, 205. 
Fuel, anthracite, value of, 90. 
Fuel economy in iron moulding, 80. 
Fuel, heating power of, to determine, 95 ; kindling, in 

iron melting, 80 ; required to melt steel in pots, 

88. 
Fuels, 86, 87 ; liquid, advantages of, 88. 
Furnace linings, fire bricks in, 27. 
Furnace, regenerative, temperature of, 89 ; in iron and 

steel melting, 89 ; refractory for melting iron, 85. 
Furniture, wood for, 220. 
Fusibility of iron, 126. 
Fusing point of metals, 7. 

GALVANIZING iron, 177. 
Gas illuminating. 98 ; economy in burning, 99 ; ap- 
proximating consumption, 100; to overcome its 
effects, 250. 
Gas, as in core making, 76. 
Gases, chimney volume of, 90. 

Gases, combustion temperature of with regenerator, 88 ; 
liquefaction temperatures of, 209; permanent, 
volume of, 3, 4, 5. 
Gear wheels, 100 ; loss by friction, 101. 
" wheels, thickness of, 101. 
" cotton press, 103. 
" size of, 101. 
German silver, composition of, 13. 

" " castings, to make, 66. 

Gin, alcohol in, 236. 

" work of a horse on, 187. 
Girders, shrinkage-in casting, 83. 
Giving brass a watery surface, 60. 
Giving patina to bronze objects, 60. 
Glass, melted, for steel tempering, 110. 
Glue, marine, composition of, 65 ; waterproof, composi- 
tion of, 65. 
Glued joints, strength of, 65. 
Glycerine in copying ink, 55. 

putty, 172. 
Gneiss as a fire stone, 36. 
Gold alloys, 7. 
" leaf, adhesive for, 165. 



270 Index. 

Gold, melting point of, 155 ; weight of, 157. 

Gooseberry wine, alcohol in, 236. 

Grain, angle of repose of, 33. 

Granite as a fire stone, 36. 

Grape sugar, 201. 

Graphite as a lubricant, 141 ; as a paint, 162 ; as a mold 

facing, 84. 
Grass green paint, 171. 
Graves wine, alcohol in, 236. 
Gravel, angle of repose of, 33 ; volume compared with 

concrete, 138. 
Gravity, 105 • specific, 234. 
Gray calcimine, 185 ; paint, 169. 
Grease, railway, 140, 141. 
Greatest cold produced, 209. 

Greeks, ancient art of hardening brass or bronze, 11. 
Green sand cores for pipe casting, 78. 
'* " castings, shrinkage of, 82. 
" " moulds, cores for, 77 ; sleeking, 79. 
Grinding aluminum, 152. 
Gun barrels, to brown, 58. 

" bronze for casting in chilled moulds, 9. 

" metal, best, 8. 

11 " castings, shrinkage of, 82. 

" " homogeneity of, 7 ; composition of, 13. 
Guns, metal for, 14. 
Gypsum, 34 ; for oil bleaching, 52. 

HAM as a force producer, 69. 
Hammering, effect of upon iron and steel, 133 ; 
shear steel, 126 ; hardening steel by, 112. 
Hard bricks, 20; spring wheat, 67; waters, to soften, 

229 ; wood, 216. 
Hardening of steels, causing alteration in length of, 
112, cracking in, 109; effect upon volume and 
density, 110; by a hydraulic press or by ham- 
mering, 112. 
Hardening springs, metal composition for, 111. 
" mill picks, 112. 

" and tempering steels, 109. 

" various substances, see also under special 

heads, 52. 
Hawksley's rule for cast iron pipe, thickness, 47. 
Hawsers, how laid up, 193. 
Headers in course masonry, 28. 



Index. 271 

Heads, feeding, 72. 

Heart wood, 214. 

Heat, effect of upon iron and steel, 133 ; of compressed 
air, 119 ; of iron in casting, 75 ; of metals in cast- 
ing, 73. 

Heating, 113. 

Heating buildings, pipe length required for, 113; given 
lengths of pipe, coal for, 114. 

Heating, effect of upon steel, 110 ; fire bricks to resist, 
27. 

Heating power of coal, 92 ; of fuel, to determine, 95 ; of 
wood, 92. 

Heaviest American wood, 214. 

Heavy oil as fuel, 94. 

Hemispherical bearings, 144. 

Hemp belts, strength of, 18. 

Hermitage wine, alcohol in, 236. 

Hickory, nutmeg, 214. 

Hide, raw, strength of, 19. 

Height of brick walls, 24. 

Hochheimer, alcohol in, 236. 

Hoisting, work done in, 241. 

Hole, flow of water through, 120. 

Honey sugar, 205. 

Hopper, triangular, dimensions of, 158. 

Horse, work and traction of, on a gin, towpath, &c, 
187. 

Horse power of a driving shaft, 190 ; for balloons, 249 ; 
from one pound of coal, 94 ; to draw air, 225. 

Hose couplings, casting, 84. 

Hot air timber seasoning, 215. 

Hooks, manner of giving way, 201 ; size required for a 
given weight, 201. 

House-building, wood for, 220. 

Human body, air pressure on, 1. 

Hungarian flours, 67. 

Hydrangeas, to darken or to redden, 186. 

Hydrated carbonate of copper, 8. 

Hydraulic cements, 136, 137. 

" jack, strength of, 119. 

" lime, 136; mortar, 136; press, hardening 

steel by, 112. 

Hydraulics, 119. 

Hydrogen, effect of upon coal, 90 ; peroxide as a disin- 
fectant, 63. 



272 



Index. 



I BEAMS, 18. 
Ice, melting point of, 231 ; saw teeth for, 195 ; spe- 
cific heat of, 231 ; weight and volume of, 230. 

Illuminating gas, to overcome its effects, 250. 

Improvement of iron by age, 135. 

Indian flours, 67 ; meal, volume and weight of, 71. 

Infusorial earth for oil bleaching, 52. 

Ingots, steel, blow holes in, 126. 

Injurious effects of various substances in fire bricks, 27. 

Ink that will copy without press or water, 55. 

Inserted tooth circular saws, 194. 

Inspection of timber, 216. 

Iron and steel, 123 ; casting mixed, 82. 
" bars, re-rolling, 132. 
" beams, 17, 18. 

" castings, 72; malleable, 86 ; stu fling, 123. 
" covered doors, 30. 

" for chains, 125 ; for wire drawing, 125 ; in build- 
ing stones, 37: in fire bricks, injurious effects of, 
27. 
" melting, coal for, 79 ; coal and coke mixing for, 
80 ; coke for, 79 ; fuel economy in, 80 ; kindling 
fuel in, 80 ; per cent, of coke in, 81 ; regenerative 
furnace for, 89. 

on stone, angle of repose of, 33. 
paints, to detect aniline in, 166. 
pipe, weight and strength of, 201. 
pyrolignite as a wood preserver, 165. 
rails, life of, 192. 
scales, oxidizing, 85. 

ship bottoms, corrosion of, 163 ; fouling of, 163. 
tank paint, asphalt and tar for, 163. 
tanks, corrosion of, 163. 
water pipes, to enamel, 57. 
carbon in, 125 ; cement for, 51. 
cast, comparison with aluminum, 158 ; rates of 
rusting, 177 ; to braze, 200 ; cold rolling, 124, 132 ; 
crystallization of by vibration, 124 ; density of, 
affected by jarring, 134; ductility of, 125, 126. 
effect of hammering upon, 133 ; of heat upon, 133 ; 
of speed of breaking upon fracture, 134 ; tempera- 
ture upon fracture, 134. 

elasticity of, 126 ; elastic limit of, 132 ; elastic re- 
sistance of, 132 ; flux for, 66 ; forging large 
masses, 133 ; fusibility of, 127 ; heat of in casting, 



Index. 273 

Iron— 

75 ; improvement of by age, 135 ; indications of 
quality, 201 ; Lowinoor, 129 ; malleable, melting, 
85; melting 3-ton block of, 80; molten, to deter- 
mine temperature of, 86 ; paint for, 181 ; purest 
known, 129; tenacity of, 132; to prevent rusting, 
177 ; weight of, 157, 231 ; welding, 131. 

Iron, wrought, tenacity of, 155; to prevent rusting, 
161 ; weight of, 177. 

Iodine as a disinfectant, 63. 

Iridium, casting, 66 ; melting point of, 155. 

Irregular figures, area of, 41* 42.* 

Isinglass as a force producer, 69. 

Italian flours, 67. 

Ivy, effect upon walls, 251 

JACK, hydraulic, strength of, 119. 
Jaggery, 206. 
Jambs, measuring, 28. 
Jarring affecting density of iron and steel, 134. 

" effect of upon rails, 135. 
Jewelers' rouge, 55. 
Johannisberger, alcohol in, 235. 
Joints, cement for, 50 ; glued, strength of, 65 ; steam 

ball and socket,-148. 
Joints for fire brick bridge walls, 27. 

" in brick work, thickness of, 25. 
Jonkoping matches, composition of, 52. 
Journals, friction of in starting, 143 ; heavy, lubricat- 
ing grease for, 141 ; paraffme for, 141 ; mill shaft- 
ing, proportions of, 141 ; pressure upon, 141. 
Judging of woods, 217. 

KINDLING fuel in iron melting, 80. 
Kitchen sink clearing, 55 
Kubanka flours, 67. 
Kyanizing, 164. 

LABORER, work of, 187. 
Lachryma wine, alcohol in, 236. 
Lacquer for steel, 162. 

Lame's rule for cast iron pipe, thickness, 48. 
Larch, shrinkage of, 174. 
Lard as a lubricant 141. 
Lathe bushes, metal for, 14. 



274 Index, 

Lathe work on aluminum, 152. 
Lavender calcimine, 185. 
Laying bridge walls, 27. 

" up of ropes, &c, 193. 
Lead, 7. 
" alloys, 7; to render resistant to hot sulphuric 
acid, 8. 
Lead-antimony alloys, 12. 
Lead-coating iron, 177. 
" color paint, 170. 
M expansion of with heat, 155, 156 ; melted, for steel 

tempering, 110. 
" paints, covering power of, 167. 
" poisoning, to prevent, 166. 

" shrinkage in casting, 83 ; silver, for mold dust- 
ing, 79 ; solvents for, 156 ; substitute for, 181 ; 
tenacity of, 155 ; weight of, 157. 
" white, blackening by sewer gas and sulphur, 166. 
Leaf woods, 214, 217. 
Leakage of boiler shells, remedying, 49. 
Leather, belt, tenacity of, 19; weight of, 18. 
Lemonade as an antitode for lead poisoning, 165. 
Length of brick walls, 24. 

" " hardened steel, alteration in, 112. 
Lengths of various things, see under their names. 
Life of rails, 191, 192. 
Lifting capacity of balloon, 106. 

'' pressure of cores, 79. 
Lighting rooms, 30. 
Lightning, striking oil tanks, 251. 
Lignum vitse for sheaves, 218. 
Lilac calcimine, 185. 
Lime, 135. 
" and tallow for bright work, 162. 
" as a disinfectant, 63 ; as a flux, 66. 
" chloride, as a disinfectant, 63. 
" dust, angle of repose, 33. 
M effect of upon timber, 216; for asphaltum roofs, 

32; for oil bleaching, 51. 
" hydraulic, 136. 

" in fire bricks, injurious effects of, 27; in fire 
stone, 34; in sand stone, effect of, 34. 
water in lubricants, 141. 
" " to prevent rust, 161. 

Limnoria, woods exempt from its attacks, 216. 






Index. 275 

Linen goods, test for purity, 55. 

Line shaft boxes, rebabbitting, 146. 

Lining elevator shafts, 30. 
44 tanks, 55, 162. 

Linseed oil, substitute for, 181. 

Liquefaction of gases, 209. 

Liquid fuels, advantages of, 88. 

Liquors, alcohol in, 235. 

Lisbon wine, alcohol in, 236. 

Litharge for molding, 78. 

Live oak, spiking, 217. 

Loading silks, 52. 

Loads for floors, 30. 

Loam castings, shrinkage of, 82. 

Locomotive cylinders, shrinkage in casting, 83. 

Locomotives, 138; consolidation, 139; tractive power 
of, 138. 

Locomotive speed affecting traction, 138. 

Locomotives, rail size for, 139. 

Locust for trenails, 63. 

Logs, weighing without balances, 233. 

Loss of foods in cooking, 70. 

Lowmoor iron, 129. 

Low steels, 129. 

Lubricant body of, 140; characteristics of good, 139; 
lard as, 141 ; soap as, 141 ; soapstone as, 141 ; ani- 
mal oil for giving body to, 140; mineral, flash 
point of, 140. 

Lubricating grease for heavy journals, 141. 
44 oil, mineral, 140. 

44 oils, test for acids, 142. 

Lubrication, 139. 

Lye for oil bleaching, 51. 

MACHINERY bearings, metal for, 14. 
Machinery oil in cores making, 77. 
Machinery, varnish for, 162; wood for, 218. 
Machinist, the term, 153. 
Mackerel as a force producer, 69. 
Madeira wine, alcohol in, 236. 
Magnesia in fire bricks, injurious effects of, 27 ; in fire 

stones, 34. 
Mahogany, how to judge, 217 ; shrinkage of, 174. 

44 stain, 180. 

Maine bricks, dimensions of, 23. 



276 



Index. 



Maize sugar, 206. 
Malaga wine, alcohol in, 236. 
Malleability of metals, order of, 155. 
Malleable brass, 13. 

" iron castings, iron for, 86; to make, 86; welding, 

86. 
" iron gear wheels, 101. 
" iron, melting, 85. 
Malmsey, alcohol in, 236. 

Malt, angle of repose of, 33 ; beer from one bushel of, 
238 ; whiskey from one bushel of, 238. 
" flour, angle of repose of, 33. 
" grain, angle of repose of, 33. 
Manganese in crucible steel, 126. 

" steel, 129. 
Manna sugar, 205. 
Man power, 187, 188 189. 
Maple, shrinkage of, 174 ; swelling of, 173, 

" sugar, 206. 
Marcobrunner, alcohol in, 236. 
Margerie process for wood preserving, 165. 
Marine engine bearings, pressures upon, 141. 

" glue, composition of, 65. 
Marsala wine, alcohol in, 236. 

Masonry, angle of repose of, 33 ; contracts for, 29 ; 
course, proportions of headers in, 28 ; course, 
strength of, 28; tine, strength of, 28; measuring 
up, 28; proportions of stone in, 28; rough, 
strength of, 28 ; scaffolds for, 29. 
" on clay, angle of repose of, 33. 
" walls, crushing strength of, 36. 
Matches, safety, composition of, 52. 
Materials, strength of, 201. 
Meal as a force producer, 69. 
" cake for oil bleaching, 52. 
" Indian, volume and weight of, 71. 
Measurements of wood, when wet, 173. 
Measures and weights of foods, 71. 
Measuring high temperatures, 207. 
" masonry, 28. 

" openings in walls, 28. 
" standing timber, 32. 
Meat, effect of salt upon, 71. 
Mechanical, 143. 

" engineer, the term, 153. 



Index. 277 

Meigs' revolution counter, 146. 

Melting iron, coal for. 79; coke for, 79 ; kindling fuel 
in, 80 ; passed off coke in, 81. 
" malleable iron, 85. 

" metals, order of putting in crucibles, 12. 
" point of alloys, 8 ; of metals, 155. 
" points of various metals and materials, see under 

special heads. 
** steel, economy in, 89 ; fuel required, 88 ; in an or- 
dinary cupola, 82. 
Mercury bichloride as a wood preserver, 164. 
'• in brass, 13. 

11 pressure of, 2 ; purifying, 156. 
Metal, Babbitt's, 13. 
Metal for valves, composition of, 13. 

" gun, 13 ; heat of in casting, 73; Muntz, 14; rates 
of rusting, 177. 
Metallic oxides, fire bricks to resist, 27. 
Metals, 6, 154 ; compression of, 112; order of ductility, 
155; expansion of with heat, 155; fusing point 
of, 7; order oi malleability ol,155; melting, 12; 
melting point of, 155 ; refractory, 155 ; saw teeth 
for, 195 , sheathing, 14 ; specific weights of, 157 ; 
tenacity of, 155 ; useful, 154. 
Meter, current, 122. 
Mexican sugar, 206. 
Mica as a fire stone, 36. 

" in fire stone, 36. 
Mild steels, 131. 
Milk as a force producer, 69. 

" sugar, 205. 
Mill picks, hardening, 112. 
" shafting journals, proportions of, 141 
" tread, work upon, 188. 
u work, woods for, 220. 
Millwrighting, 159. 
Milwaukee bricks, dimensions of, 23. 
Mineral lubricating oil, 140. 
Mineral wool, action on iron, 55. 
Mine shafts, ascension of air in, 223 ; motive column of 

air in, 226. 
Miscellaneous, 247. 

Mixing coal with coke in iron melting, 80. 
Mixture for filling cracks in wood, 172. 
Molasses in stucco, 137. 



278 Index, 

Mold facing, graphite, 84. 
H for steel castings, 85. 
Molding, iron, economy in, 80. 
letting off', 78. 
" sand for, 78. 

Molds, drying, 76; dusting, 79. 
" green sand, sleeking, 79, 
" silica, 85. 
Molten iron, to determine temperature of, 86. 
Mortar, effect of age on, 138 ; hydraulic, 136 ; in brick 
walls, strength of, 24 ; in brick work, proportion 
of, 24, 137 ; influence upon strength of brick 
work, 21 ; in stone work, proportions of, 137. 
Mortars, 135. 
Moselle, alcohol in, 236. 
Moss for oil bleaching, 52. 
Motive column of air in mine shafts, 226. 
Mucilage, flexible, 49. 
Muntz metal, composition of, 14. 
Muscat wine, alcohol in, 236. 
Mushet's steel ; 128. 
Musk, deodorizing, 57. 
Mutton, loss in cooking, 7G*. 

NAILS, force to drive, 64; resistance to drawing, 63 • 
resistance to driving, 63. 
Naming steels, 129. 
Narrow saw kerf, saving by, 195. 
Neatsfoot oil for spring hardening, 111. 
Nickel alloys, 13. 

" weight of, 157. 
Nitric oxide as a disinfectant, 63. 
Nitrogen, liquefaction of, 209. 
North light, quality of, 177. 
North River bricks, dimensions of, 23. 
Number of bricks per square foot of wall, 23. 
Nutmeg hickory, 214. 
New York bricks, dimensions of, 23. 

OAK for building, 218; for trenails, 62. 
Oak, live, faults of, 217. 
Oak, shrinkage of, 174; swelling of, 173; white, faults 

of, 217. 
Oat meal as a force producer, 69. 
Octyl-chlorides, 53. 



Index. 279 

Oil, animal, for giving body to lubricants, 140; boiled, 
to make, 171 ; chlorine test for, 148 ; cod hver : as 
a force producer, 69 ; composition for hardening 
springs, 111; consumption of, estimating, 142; 
cooking in, 69; figures, 142; fish, for steam boil- 
ers, 164; for putty, 171; heavy, as fuel, 94; in 
limestone, 36; in" varnish, objections to, 168; 
dead, as a wood preserver, 165 ; linseed, substitute 
for, 181; machinery, in core making, 77; meal 
cake for oil bleaching, 52 ; mineral, lubricating, 
140. 

Oil paintings, to restore varnish on, 174. 
" refining, 52. 

Oils, 161. 
" animal, test for, 142 ; bleaching, 51, 52. 

Oil seasoning timber, 215 ; advantage of, 218. 

Oils, lubricating, testing for, 141. 

Oil, sperm, as a lubricant, 140. 

Oils, vegetable, test for, 143. 

Oil tanks, struck by lightning, 251. 

Old gold paint, 171. 

Olive green paint, 171. 

Openings in walls, measuring, 28. 

Ordinary bricks, dimensions of, 23. 

Oregon flours, 67. 

Oxidizing, 85. 

Oxygen, liquefaction of, 209. 

PAINT, as a cause of dry rot, 169 ; asphalt for iron, 
163; black, for smoke stacks and boiler fronts, 
162 ; black lead as a, 162 ; for floors, 181 ; for iron, 
181 ; for roofs and fences, 181 ; for ships' bottoms, 
164 ; for zinc, 181. 

Paint for various materials, and places, see under 
their names. 

Painting iron, 177. 

Paintings, exposures best for, 169 ; oil, to restore var- 
nish on, 174. 

Paints, 161 ; covering power of, 167 ; for standing clim- 
ate, 165 ; iron, to detect aniline in, 166 ; spreading 
power of, 167 ; tar for iron, 163 ; to resist sewer 
gas, 166. 
u various colors, see under names of the colors. 

Pale bricks, 20. 

Palm oil for railway grease, 140. 



280 Index. 

Palm sugar, 206. 
Panel putty, 172. 
Paper making rolls, testing, 247. 
" sugar, 201. 
44 to make water proof, 163 : water proof building, 

29. 
Para, alcohol in, 236. 
Paraffin, as a water proof compound, 163 ; for heavy 

journals, 141 ; melting point, expansion, &c, 53. 
Patent leather, to keep, 175. 
Patina, 8 ; to give, 60. 
Pattern making, wood for, 218. 
Patterns, allowance for core weight, 232 ; to find weight 

of castings from, 232; pounding, 78; tucking up, 

78. 
Paving, work done at, 245. 
Peach blossom paint, 170. 
Pearl grey paint, 169. 

Pearwood, shrinkage of, 174 ; Swelling of, 173. 
Peas, angle of repose of, 33 ; chick as a life sustainer, 

69. 
Peat as a deodorizer, 63 ; for oil bleaching, 52. 
Pencil drawings, to make inerasable, 252. 
Perforated bricks, 22 ; strength of, 20. 
Perfume, perpetual, 57. 
Permanganate of potash as a disinfectant, 63 ; for oil 

bleaching, 52. 
Peroxide of hydrogen as a disinfectant, 62, 63. 
Perpetual perfume, 57. 
Persian flours, 67, 

44 wheel, work done at, 244. 
Petunias, to darken, 186. 
Philadelphia bricks, 23. 

44 front bricks, dimensions of, 23. 

Phosphor bronze for worm wheels, 151. 

44 " gear wheels, 101. 

Phosphorus as a flux, 66 ; in ancient bronze weapons, 

11 ; in steel, 128. 
Photometer, comparative, 99. 
Picks, mill, hardening, 112. 
Pigment, black, 166. 
Pile driving, work done at, 246. 
Piles, various, see under special heads. 

44 of shot, volume of, 46. 
Pillars, flat ended, strength of, 218. 



Index. 281 

Pin, crank, see crank pin. 

Pine wood, how to judge of, 217 ; shrinkage of, 174 ; 

strength of, 123. 
" yellow, stain for, 178. 
Pipe casting, green sand for, 79. 
" coal required for heating given lengths of, 114. 
" length required for steam heating buildings, 113, 

115, 117. 
Pipes, brass, squirting, 8 ; cast iron, rules for strength 

and thickness or, 48 ; flow of air in, 224. 
Pipe, round, required area of, 42. 
Pipes, shrinkage in casting, 83. 
" steam, charring wood by, 87 ; for ventilating 

flues, 222. 
" thickness and strength of, 47, 48; volumes of, 44 ; 

wrought iron, strength of, 201. 
Piston rods, strength of, 148. 
Pitch of shingle saws, 196. 
Pivots, swing bridge, pressure upon, 141. 
Planimeter, measuring areas by. 39. 
Plants, 185 ; climbing, effects or upon walls, 251 ; in a 

sleeping room, 186. 
Plaster of Paris, 34 ; as a flux for steel, 130 ; delaying 

setting, 136 ; hardening, 53, 54. 
" roofs, weight of, 30. 
Platinum, melting point of, 155 ; solvents for, 156. 
Pocket, coal, capacity of, 43. 
Plowing in stiff soil,* day's work, 30. 
Poisoning, lead, to prevent, 166. 
Polish flours, 67. 
Polishing aluminum, 151. 
Poplar, shrinkage of, 174. 
Porous bricks, 22 ; strength of, 20. 
Porter, alcohol in, 236 ; as a force producer, 69. 
Portland cement, 136 ; English, 136 ; in brick work, 21, 

25. 
" sandstone, durability of, 37. 
Port wine, alcohol in, 237. 
Potash as a flux, 6Q ; in fire bricks, injurious effects of, 

27 ; in fire stones, 36. 
" permanganate as a disinfectant, 63 ; for oil 

bleaching, 52. 
Potato brandy, flavoring matter in, 237. 
Potatoes as force producers, 69. 
Potato ether, 239. 



282 Index. 

Potato spirit, 239. 

Pounding a pattern, 78. 

Power, 186 ; carried by a shaft, 191, 187, 188, 189 : steam, 
cost of, 186 ; transmission of by rarefied air, 189. 

Prepared chalk, to make, 178. 

Pressure borne by bricks, 20. 

" effect of upon coefficient of friction, 143. 
" exerted by brick walls, 25. 

" of atmosphere, 1, 2 ; of mercury, 2 ; of various 
liquids, etc., see under special heads, 225 ; of 
water, 2; one atmosphere of, 2; on walls, 20; 
upon journals and bearings, 141. 

Primary rocks as fire stones, 36. 

Prints, allowance for weight of in patterns, 232. 

Proportion of carbon in anthracite coal, 93 ; in bitu- 
minous coal, 93. 
" of coal to iron in reheating furnaces, 88. 

Proportions of stone in masonry, 28. 

Propyl alcohol, detection of, 238. 

Puddled iron, cold rolling, 132. 

Pump barrels, cylindrical foot in measuring, 44. 
" work done at, 188, 243. 

Purest known iron, 129. 

" water, soil to give, 229. 

Purifying mercury, 156. 

Purity of various substances, testing for, see under 
special heads, 55. 

Purple paint, 170. 

Putty, glycerine, 172 ; panelling, 172 ; to make, 172 ; 
water glass, 172. 

Pyrites in fire bricks, injurious effects of, 27. 

Pyrolignite of iron as a wood preserver, 165. 

Pyrometer, to make, 207, 

QUALITY of iron, how to determine, 201. 
Quality of sun lights, 177. 
Quartz as a fire stone, 36 ; in fire stone, 36. 
Quicklime as an antiseptic, 62 ; as a disinfectant, 62, 

63 ; for oil bleaching, 51. 
Quicksilver, capacity of for heat, 119. 

RAIL distance, 191. 
Railroad grease, 140. 
Rails, Bessemer, life of, 192. 



Index. 283 

Rails, effect of jarring upon, 135 ; expansion of, 191 ; 

iron, life of, 192. 
Rail size required for locomotives, 139. 
Rails, life of, 191, 192. 

" steel, life of, 192. 
Railway grease, palm oil for, 140 ; tallow for, 140. 
Railways, 191. 

Raisin wine, alcohol in, 236. 
Rake of saw teeth, influence upon the cut, 195. 
Rarefied air for transmission of power, 189. 
Raw hide, strength of, 19. 
Razor steel, 130. 
Reaumur scale, 206. 
Re-babbitting line shaft boxes, 146. 
Recording revolution counter, 146. 
Reddening brass by hydrochloric acid, 59. 
Red shortness in steel, to correct, 126. 
Reentrant outlines, areas of figures with, 41. 
Refining oils, 52. 

Refractory building stones, 36 ; metals, 155. 
Regenerative furnace in iron and steel melting, 89 ; 

temperature of, 80. 
Re-hardening steel, 134. 
Removing smells, 62. 
Repose 2 angle of, 32, 33. 
Re-rolling iron bars, 132. 

Resin for spring hardening, 111 ; in core making, 76. 
Reuleaux' rule for cast iron pipe, thickness, 48. 
Reverberatory furnace for melting iron, 85. 
Revolution counter, Meigs', cording, 146. 
Rhenish wine, alcohol in, 236. 
Rice as a force producer, 69. 
River sand for mortar, 137. 
Rivers, colors of, 228; waters of, 228. 
Rivets, test for, 125. 
Roasting, loss of meats in, 70. 
Rocks, primary, as fire stones, 36. 
Rods, connecting, strength of, 148 ; piston, strength of, 

148. 
Rolling iron, 124 ; shear steel, 12G ; zinc, 156. 
Rolls for paper making, 249. 
Roman cement, 136. 
Roofe and fence, paints for, 181. 

" asphalt. 31; corrugated, 30; maximum weights 

for, 30, 



284 Index, 

Roofs, slate, 30 . coal tar for, 29 ; flat pitched, 29. 

" snow weight on, 30; weights for, 30; wind force 
on, 30. 
Rooms, lighting, 30. 
Ropes, 193. 

" laying up of, 193 ; new, strain that they can bear, 
201. 
Rose calcimine, 185. 
Roses, to darken, 186. 
Rot, dry, 216 ; causes of, 169. 
Rouge, jewelers, 55. 
Rough masonry, strength of, 28. 
Round pipe, required area of, 42. 

" shot in a complete pile, 46 ; in a square pile, 46 ; 
in a triangular pile, 46. 

" timber, volume of, 45. 
Rudesheimer, alcohol in, 236. 
Rum, alcohol in, 236. 
Runners, disadvantage of, 77. 

Rupture of material caused by repeated strains, 133. 
Russian flours, 67. 
Rusting, to keep files from, 161. 

" of iron, prevention of, 177 ; of metal, rates of, 177 ; 
of steam boilers, composition to prevent, 164. 

" see under names of materials, 

" steel, to keep from, 161. 
Rust joint mixture, 50, 148 

SAFETY matches, composition of, 52. 
Safe working strain of leather belts, 19. 
Sal ammoniac in rust joint mixtures, 148. 
Salmon bricks, 20. 
" paint, 170. 
Salt, as an antiseptic, 62 ; effect of upon meat, 71 ; for 

bleaching oils, 51. 
Saltpetre as an antiseptic, 62. 
Sammel bricks, 20. 
Sand, angle of repose of, 33. 
" for core making, 77 ; for mortar, 137 ; for mould- 
ing, 78 ; for oil bleaching, 52. 
" green, for pipe casting, 78. 
" moulds, sleeking, 79. 
Sandstone, bush hammering, 28; effect of lime in, 34 ; 
how to lay, 34; durability of Portland, 37; tests 
of, 34. 



Index. 285 

Sandstone, walls, scaling in. 28. 

San it as as a disinfectant 62. 

Sap causing decay in wood, 169. 

Sauterne, alcohol in. 236. 

Saving by narrow saw kerf, 195. 

Saw, band, detachable, 196 ; tension upon, 196. 

" blades, thickness of, 195. 

" kerf, saving by narrow. 195. 

" mill, band, capacity of, 197-8. 
Saws, 194. 

" circular, set for, 194 ; two-high, 195. 
Saw steel, 130. 

'• teeth for soft wool, 195. 

" teeth for various materials, see under their names. 
Scaffolding for masonry, 29. 
Scales, Baume, 234. 
Scale, iron, 85. 
Scales, see balances, 233. 

M thermometer, 206. 
Scaling in sandstone walls, 28. 
Schiele antifriction curve for bearings, 144, 145. 
Schist for oil bearing, 52. 
Screening coal, 73. 
Screw, force of, 43 ; strength of, 119. 
Sea level, air pressure at, 2. 

" pressure of at great depths, 250. 

" sand for mortar, 137. 
Separation of components in alloys, 7. 
Sot for circular saws, 194. 
" spread, for saws, 194; spring, 194. 
Sewer gas, blackening white lead, 166; paint to resist, 

166. 
Shaft, bearings, cylindrical, 143; fiat, 143; vertical, 143, 
44. 
" driving, diameter of, 190 ; horse power of, 190. 
Shafting, 189; cold rolled, 124. 

M journals, proportions of, 141. 
" twisting stress upon, 189. 
Shaft, power carried by, 191. 
Shafts, elevator, fire proof, 30 , mine, motive column of 

air in, 226. 
Shear steel, working, 126. 
Sheathing metal, composition of, 14. 
Sheaves, lignum vita 1 for, 218. 
Sherry, alcohol in, 236. 



286 Index. 

Shingle saws, pitch of, 196. 

Ship bottoms, iron, corrosion and fouling of, 163. 
" " paint for, 164. 

" building, woods for, 218. 
Shipping bright work, 162. 
Shiraz, alcohol in, 236. 
Shot, volume of, 46. 
Shrinkage in castings, 74 ; of green woods, 174. 

" of metals and objects in casting, see under name 
of metal or object. 

" of various woods, see under their names. 

" rules, 82. 
Shrouds, how laid up, 194. 

Silica as a mould, 85 ; flux for, 66 ; in fire bricks, 27. 
Silicon bronze and tin-zinc alloys, 10. 

in steel, 129. 
Silks, loading or weighting, 52. 
Silver alloys, 7. 

" lead for dusting moulds, 79. 

" melting point of, 155. 

" paint, 170. 

" weight of, 157. 
Sinks, to clear, 55. 

Skin of wrought iron, strength of, 124. 
Slate as a fire stone, 36. 
Slate roofs, coal tar for, 29 ; flat pitched, 29 ; weights of, 

30. 
Sleeking green sand moulds, 79. 
Sleeping room, plants in, 186. 
Slide rule, lines and lettering on, 37. 
Sliding wheels, 149. 
Smell destroyers, 63. 

" disguisers, 62. 

" removers, 63. 
Smoke stacks, black paint for, 162. 
Smooth castings, cores for, 77. 

" iron castings, 83. 
Snow melting, steam for, 117, 118. 
" weight and volume of, 230. 
11 " on roofs, 30. 

Soap as a lubricant, 141. 
Soapstone as a lubricant, 141. 

Soda as a flux, 66 ; for oil bleaching, '52 ; for railway 
grease, 141 • in fire bricks, injurious effects ol, 27. 
" lye for oil bleaching, 51. 



Index. 287 

Soft bricks, 20. 

Softening hard waters, 229. 

Soft steels, 129 ; weight of, 157. 

" winter wheat, 67. 

" wood, 216; saw teeth for, 195. 
Soil to give purest water, 229. 
Solder, fusible, 199. 
Soldering aluminum, 199. 
Solder melting in boiling water, 199. 
Solders, 199. 

Solvents for lead, 156 ; for platinum, 156. 
Sorghum sugar, 206. 
South light, quality of, 177. 
Specific gravity, 234. 

u weights of materials, see under their names. 
Speed affecting locomotive traction, 138. 

" of breaking iron and steel, effect of upon frac- 
ture, 134 ; of working metals, effects of, 135. 
Speeds, various, see under names. 
Spermaceti (sperm) oil for spring hardening, 111 ; as a 

lubricant, 140. 
Spheres, volume of, 45, 46. 
Spherical shot, diameter of, 46. 
Spiegeleisen in steel making, 128. 
Spikes, resistance to drawing, 64. 
Spiking live oak, 217. 
Spindle steel, 131. 
Spinning aluminum, 153. 
Spiral, wire to wrap cylinders in a, 43. 
Spirit, potato, 239. 

Spirits and ethers, difference between, 238 
Spirit, wood, 239. 
Splining cold rolled shafting 124. 
Spoons, capacity of, 72. 
Spreading power of paints, 167. 
Spread set for saws, 194. 
Spring hardening, oil composition for, 111. 
Springs, blazing off, 111. 
Spring set for saws, 194. 
Springs, tempering, 110, 111. 
Squaring felled timber, 215. 
Stacks, volume of brick work in, 26. 
Stains for various materials, see under names, 178. 
Staining brass dark violet, 59 ; golden orange, 59. 
Stale bread, restoring to freshness, 68. 



288 



Index, 



Standing timber, measuring, 32. 
Starch sugar, 201. 

Starting, friction of journals in, 143. 
Steam boilers, composition to prevent rusting, 164 : fish 
oil for, 164. 
" Engineer, cylindrical foot for, 44. 
" for oil bleaching, 51. 
" heating, pipe length required for, 113. 
Steaming timber for bending, 215. 
Steam joints, ball and socket, 148. 

" pipes, charring wood by, 87 ; for ventilating flues, 

222 ; thickness of, 47. 
11 power 2 cost of, 186. 
11 quantity ot for snow melting, 117. 
Stearine, melting point, expansions, &c, 53. 
Steel, 123. 
" and iron, casting mixed, 82. 
" annealing, 110 ; antidote for sulphur in, 126 ; 
Bessemer, theory of, melting, 127 ; borax for 
welding, 110. 
" bridges, loads for, 30. 

" case hardening, 131 ; casting, welding, 130 ; cast- 
ings, molds for, 85 ; Chester, 132 ; chisel, 131 ; 
cold rolling, 132 ; cold short, 128 ; compressing, 
132 ; crucible, manganese in, 126; temperature of 
making, 127. 
" chrome, tempering, 111. 
" density of, affected by jarring, 134. 
" effect of copper upon, 129 ; effect of hammering 
upon, 133 ; effect of hardening upon volume and 
density, 110 ; effect of heating upon, 110, 133 ; ef- 
fect of speed of breaking upon fracture, 134 ; effect 
of temperature upon fracture, 134. 
file, 131. 

flux for welding, 110 ; forging large masses, 133 ; 
fuel required to melt, 88 ; hammering, 126. 
hardened, alteration in length of, 112. 
ingots, blow holes in, 126. 
lacquer for, 162. 

making, direct process of, 127 ; spiegeleisen in 
melting, 128. 
manganese in. 129. 

melting, economy in, 89 ; in ordinary cupola, 82 ; 
regenerative furnace for, 89. 

mixing with cast iron 2 81 ; Mushet's, 128 ; phos- 
phorus in, 128; proportion of carbon in, 126. 



Index. 289 

Steel, rails, life of, 192. 
u rate of rusting, 177 ; razor, 130 ; red shortness in, 
to correct, 126 ; re-hardening, 134 ; rolling, 126 ; 
saw, 130. 
" cracking in hardening, 109 ; distinguishing, 129 ; 
expansion of in hardening, 110; for boiler and 
bridge work, 109. 
" shear, working, 126; silicon in, 129; low, 129; 

molds for, 231 ; naming, 129. 
" soft, weight of, 157. 

" percentage of carbon in, 130; soft, 229; spindle, 
131 ; tempering, 130, 131 ; tempering and harden- 
ing, 109 ; twisting in hardening, 109 ; sulphur in, 
129 ; warping, in hardening, 109. 
'* tempered, adjusting density of, 134 ; tempering, 

134 ; tempering in melted lead and glass, 110. 
" tenacity of, 155 ; tool, 131 ; to prevent from rust- 
ing, 161 ; to remove sulphur from, 127 ; tungsten 
in, 127, 128 ; weight of, 157, 231. 
" welding, 129 ; Askew on, 130. 
" wolfram in, 128. 
Stock brick, 22. 
Stone, angle of repose of, 33. 
Stonebeach bricks^ dimensions of, 23. 
Stone, building, disintegration of, 37; durability of, 37; 
iron in, 37 ; water in, 37. 
" color paint, 171. 

" fire, injurious constituents in, 34, 35, 36. 
" proportions of in masonry, 28. 
" sand, how to lay, 34 ; tests of, 34. 
Stones, building, 34. 
Stone walls, scaling in, 28. 

" work, proportion of mortar in brick work, pro- 
portions of mortar in, 137. 
Stout, alcohol in, 236. 

Strains, repeated, rupture of material caused by, 133. 
Strain that ropes can bear, 201 ; upon brick work, 22. 
Straw color calcimine, 185 ; paint, 170 
Stream, flow of water through, 120. 

u u wavs f or measuring, 121. 

Strength of alloys, 8; of cast iron pipes, 47 ; of materi- 
als, 201 ; of mortar in brick walls, 24 ; of various 
materials, see under various heads, 46. 
Striking velocity of a falling body, 109. 
Strongest American wood, 213. 



290 Index. 

Stucco, 137 ; molasses in, 137 ; sugar in, 137. 

Stuffing iron castings, 123. 

Substitute for lead, 181 ; for linseed oil, 181. 

Suet, beef, for spring hardening, 111. 

Sugar as a force producer, 69 ; in stucco, 137 ; volume 

and weight of, 71. 
Sugars, 201 ; various kinds, see under their special 

names. 
Sulphate of copper as a wood preserver, 165. 
Sulphur, effect upon lead paints, 166. 
Sulphuric acid, alloys to resist, 8; for oil bleaching, 51 ; 

tank for, 55. 
Sulphur in steel, antidote for, 126, 129 ; effect of, 129 ; to 

remove, 127. 
Sulphurous acid as a disinfectant, 63. 
Sulphur, removing from coke, 87. 
Sunlight, quality of, 177. 
Swedish safety matches, composition of, 52. 
Sweet bread, flour required for, 67. 
Swelling of various woods, see under their names, 173. 
Swing bridge pivots, pressures upon, 141. 
Syenite as a fire stone, 36. 

TALLOW and lime for bright work, 162. 
Tallow and white lead for bright work, 162. 

Tallow for railway grease, 140. * 

Tamarack, 214. 

Tank for sulphuric acid, 55. 
" lining, 162. 
" paint, asphalt for, 163 ; tar for, 163. 

Tanks, 163 ; iron, corrosion of, 163 ; oil, struck by light- 
ning, 251. 

Tar for iron tank paint, 163 ; for oil bleaching, 52. 

Tarring, effect upon cordage, 194. 

T beams, 17. 

Tea, beef, how to make, 70. 

Teacup, capacity of, 72. 

Teeth, inserted, for circular saws, 194. 

Teeth, saw, see saw teeth, 195. 

Temperature, effect of upon fracture of steel and iron, 
134 ; of combustion gases with regenerator, 89 ; of 
combustion of charcoal, 87 ; of making alloys, 12 ; 
of molten iron, to determine, 86 ; of regenerative 
furnace, 89. 

Temperatures, 206 ; high, method of measuring, 207 ; 
various, see under special heads. 



Index. 291 

Tempering and hardening steels, 109. 

" annealed bronze, 113 ; chrome steel, 111 ; springs, 

110, 111. 
" steel, 130, 131, 134; in melted lead and glass, 110. 
Tenacities of materials, see under names of metals. 

" " metals, 155. 

Teneriffe wine, alcohol in, 236. 
Tensile strength of wrought iron, 123. 
Teredo, woods exempt from its attacks, 216. 
Testing various substances, see under special heads, 52. 
Theatre floors, loads for, 30. 

Thickness of brick walls, 24 ; of cast iron steam pipe, 
47 ; of various objects, see under special heads, 46. 
Thin cores baking, 76. 
Three-ton block of iron, melting, 80. 
Thurston's bronze, 9. 
Timber and trees, 213. 

Timber, angle of repose of, 33 ; characteristics of good, 
213 ; inspection of, 216 ; oil-seasoning, 218 ; on 
stone, angle of repose of, 33 ; round, volume of, 45. 
" seasoning, hot air, 215 ; oil, 215. 
" squaring, 215 ; standing, measuring, 32 ; steaming, 
215 ; strength of, 218. 
Tin, 7. 
" alloys, 7, 13. 

" chloride for weighting silks, 52. 
" expansion of with heat, 155, 156. 
" lining for elevator shafts, 30. 
Tinned iron for tire proof doors, 30. 
Tinning iron, 177. 
Tin, shrinkage in casting, 83; tenacity of, 155; test of, 

8. 
Tobacco ash, amount taken from the soil, 238. 
Tokay, alcohol in, 236. 
Ton, cubic feet of coal in, 43. 
Tool steel, 131. 

Tooth rake, influence upon the cut, 195. 
Tough woods 218. 
Tower clock dials, to gild, 165. 
Tow path, work of a horse on, 187. 
Traction of a horse, 187. 
Tractive power of locomotives, 138. 
Tractrix curve, 144. 

Train lengths, 192 ; speed, to determine, 193. 
Transmission of power by rarefied air, 189. 



292 Index, 

Trapeziums, areas of, 38. 

Trautwine's rule for cast iron pipe, thickness, 48. 

Travelling in deserts, foods for, 69. 

Tread mill, work upon, 188. 

" wheel, work done at, 242. 
Trees, 213 ; cinnamon, 186 j felled, barking, 215. 
Trenails, 63. 

Triangles, areas of, 39, 40. 
Troy, bronze weapons from, 11. 
True measurement of standing timber, 32. 
Tucking up a pattern, 78. 
Tumbler, capacity of, 72. 
Tungsten in steel, 127, 128. 
Turbine wheels, cardinal principle of, 120. 
Turnip-shaped body, volume of, 45. 
Tuyere area, 81. 
Twisting of wheels in hardening, 109. 

" stress upon shafting, 189. 
" Two high " circular saws, 195. 
Tympan, work done at, 244. 

UNIVERSAL cement, 49. 
Useful metals, 154. 

VALUE of anthracite fuel, 90. 
Values of foods as force producers, 69. 

Valve faces, chaplets in casting, 75. 
" metal, 13. 

Varnish cracks, science of, 168. 

Varnishes, 161. 

Varnish for machinery, 162 ; for walls, 176 ; oil in, 168 ; 
on oil paintings, to restore, 174; reason for its 
effects, 167 ; whitening of on oil paintings, 169. 

Veal as a force producer, 69. 

Vegetable charcoal for oil bleaching, 52. 
" oils, test for, 143. 

Velocity of cannon balls, 252 ; of falling bodies, 107, 108. 

Ventilating flues, steam pipes for, 222. 

Ventilation, 220. 

Ventilator, air discharged by, 221. 

Venting thin cores, 76. 

Vertical shaft bearings, 143, 144. 

Vessels, wooden, copper fastenings for, 63. 

Vibration, crystallization of iron by, 124. 

Vibrations of earth, to observe, 250. 



Index. 293 

Vinous odor of wine, 237. 

Violet paint, 170. 

Volume of air, 3, 4, 5, 6 ; of brick work in chimneys, 20 ; 
of chimney gases, 90 ; of gas, 3, 4, 5 ; of steel, af- 
fected by hardening, 110 ; of water, 178. 

Volumes of bodies and materials, see under their spec- 
ial heads ; of cylinders, 44 ; of pipes, 44. 

WALLA W alia flours, 07. 
Walls, beton, fire proof qualities, 36. 
Walls, brick, pressure exerted by, 25; proportions of, 
24 ; weight of, 25. 
" concrete, fire proof qualities, 36. 
* effect of ivy upon, 251 ; effects of woodbine upon, 
251 ; foundations for, 25 ; pressure on, 20 ; varnish 
for, 176. 
Walnut, shrinkage of, 174. 
Worm wheels, phosphor bronze for, 151. 
Warping, cause of, 216. 

" of steels in hardening, 109. 
Water absorbed by building stones, 36 ; as a hardening 
fluid for steel, 111. 
" bilge, to neutralize corrosive action of, 163. 
" capacity ol for heat, 119 ; contained in wheat 

bread, 68 ; evaporation of, work done by, 246. 
" flow of in a stream, 120 ; through a hole, 120. 
" glass putty, 172. 
" in core making, 77. 

11 lime, in lubricants, 141 ; to prevent rust, 161. 
" pipes, to enamel, 57. 
" pressure of, 2, 226, 250. 
u purest, 229 ; soil to give, 229. 
" proof building paper, 29 ; compound, 163 ; glue, 
composition of, 65 ; paper, 162. 
Waters of rivers, 228. 

Water, specific heat of, 231 ; taken up by flour in dough- 
ing, 68; volume of, 178; weight of, 177, 178; 
weight of cylindrical foot of, 44 ; well, to purify, 
229. 
" work done by evaporation of, 246. 
" works, cylindrical foot for, 44. 
Wax as a water proof compound, 163. 
Waxing floors, good mixture for, 178. 
Ways for measuring stream flow, 121. 
Wedgwood pyrometer, 207, 



294 Index. 

Weighing the earth, 105 ; truly on false balances, 233. 
Weight doubling, 38. 

" of air, 1 ; of brick walls, 25 ; of castings from pat- 
terns, 82 ; of cylindrical foot of water, 44 ; of 
water, 177, 178. 
" estimating areas by, 42. 
Weights, 67, 230. 

" and measures of food, 71. 

" of various objects and materials, see under spec- 
ial heads, 46. 
Weighting silks, 52. 
Welding, atmosphere for, 125. 
" cast steel, 130 ; iron, 131. 
" steel, Askew on, 130 ; flux for, 110. 
Well water, to purify, 229. 
West light, quality of, 177. 
Wet bread, water in, 68. 

Wetting and drying as a cause of dry rot, 169. 
Wet wood, compressive strength of, 218. 
Wheat flour, angle of repose, 33 ; as a force producer, 
69 ; volume and weight of, 71. 
" grain, angle of repose of, 33. 
Wheels, gear, 100. 
" sliding, 149. 

" turbine, cardinal principle of, 120. 
14 worm, 149. 
Whiskey, alcohol in, 236 ; amount from one bushel of 

malt, 238 ; economy in making, 237. 
White brass, composition of, 13. 
" bread, flour required for, 67. 
" bronze, composition of, 12. 
" lead and tallow for bright work, 162. 
" lead, blackening with sewer gas, 166. 
Whitening aluminum, 58 ; brass 59. 

" of varnish on oil paintings, 169. 

Whitewash, everlasting, 182 ; fire proof, 182. 
Whiting, 172. 

Willesden waterproof building paper, 29. 
Wilmington bricks, 23. 
Winch ell's cement, 49. 
Wind force on roofs, 30. 
Windmill, work done by, 247. 
Window openings, measuring, 28. 
Wine, bouquet of, 237. 
11 glass, capacity of, 72. 



Index. 295 

Wines, 235 ; acidity of, 235 ; alcohol in, 235. 
" and beers, distinctions between, 236. 
Wine, vinous odor of, 237. 
Wire drawing, iron for, 125. 

11 quantity to wrap about a cylinder in a spiral, 43. 
Wolfram in steel, 128. 

Wood, action of air upon, 168; best age for charcoal 
making, 87 ; charring by steam pipes, 87 ; cracks 
in, 171 ; decay in, 168. 
Woodbine, effect of upon walls, 251. 
Wooden beams, breaking weight of, 15. 

" gear wheels, 101. 
Wood ether, 239. 
" filling, 173. 
" for pattern making, 218. 
" hard, 214, 216. 
11 heating power of, 92. 
" measurements of when wet, 173. 
11 on stone, angle of repose of, 33. 
" on wood, angle of repose of, 33. 
" pine, strength of, 123. 
" preserving solutions, 164, 165. 
" sap in, 169 ; at what age to cut, 214 ; at what sea- 
son to cut, 214, 217 ; elastic, 218 ; for various pur- 
poses, see under special heads, 218 ; green, shrink- 
age of, 174; leaf, 217 ; soft, 216 ; saw teeth for, 195. 
Woods, see under specific name as ash, oak, etc. 

" strength of glued joints in, 65; strength of, in 
various directions, 218 ; tough, 218. 
Wood spirit, 239. 

Wool, mineral, action of on iron, 55. 
Work, 239. 

" day's standard for laborer, 239. 
" done at Archimedean screw pump, 244 ; at chain 
pump, 244 ; at crank, 240 ; at paving, 245 ; at Per- 
sian wheel, 244 ; at pile driving, 246 ; at pumping, 
188, 243 ; at tympan, 244 ; by evaporation of water, 
246; by windmill, 247 ; in hoisting, 241 ; in turn- 
ing a crank, 187 ; upon a treadmill, 188 ; with a 
crane, 188. 
Worked copper, tenacity of, 155. 
Working cork, 251. 

Workman's capacity in brick laying, 29. 
Work of a brick layer, 23. 

" of a horse, 187 ; upon a gin, 187 ; upon a tow path, 
187. 



296 Index. 

Work of a laborer, 187. 

" affected by speed, 135. 
Worm wheels, 149. 
Wrought iron, fibre of, 123. 

" iron gear wheels, 101 ; pipe, strength of, 201. 
" " rate of rusting, 177 ; strength of, 125. 
M " strength of skin of, see also wrought iron 
iron castings, malleable iron, tenacity of, 155 
tensile strength of, 123; to prevent rusting, 161: 
welding power of, 125. 

YELLOW brass, composition of, 13. 
Yellow paint, 170. 
Yellow pine, stain for, 180. 

ZINC, 7. 
Zinc alloys, 13. 
Zinc and copper alloying, 11. 
" " tin, expansion of, 156. 
" castings, 156. 
" chloride as an antiseptic, 62 ; for oil bleaching, 

52 ; for wood preserving, 165. 
" expansion of with heat, 155, 156. 
" lead alloys, 12. 
" paints, covering power of, 167. 
" shrinkage in casting, 83; tenacity of, 155; to 
bronze, 58 ; to copper, 59. 



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